Volume 36 (06) November 2024

The scarcity of natural sand in wall construction poses a significant challenge, prompting a novel solution in this study: wall panels using Recycled Concrete Aggregates (RCA) and perlite. The lack of existing literature on such panels underscores the study’s importance. Panels of varying thicknesses (75 mm, 100 mm, and 125 mm) are prepared with a 1:4 concrete mix, with the aggregate portion consisting of 40% sand, 40% RCA, and 20% perlite. For control purposes, additional wall panels are prepared using natural sand as the aggregate. Subsequently, all panels undergo compressive tests to evaluate their structural performance, including crack analysis. Comprehensive analyses, encompassing load, stress, and strain, yield Young’s Modulus and Poisson’s Ratio. Strain gauges and acoustic emissions enhance data precision. Maximum loads of 936.51 kN are observed on 125 mm panels. Findings reveal variations in compressive strength, with control panels surpassing the proposed ones. Wall panel thickness proves pivotal, influencing both strength and crack visibility. Notably, the 100 mm panel performs optimally, displaying minimal percentage differences in compressive strength compared to the control. This research offers invaluable insights into alternative aggregate-infused wall panels’ structural behaviour, enriched by verification through an AE analysis.

Keywords : Recycled concrete aggregates; perlite; wall panels; compressive tests; structural performance

The utilization of precast wall panels has gained prominence due to its potential for enhancing construction speed, quality, and sustainability. One critical aspect of precast construction is the connection between wall panels, where it is one of the proven to be the weakest link in the system. Rigidity of the connection between panels was also a point of concern. This research aims to investigate the mechanical performance of the dapped wet connection model in the vertical wall-to-wall connection in application for precast wall panels, particularly focusing on shear load considerations. The investigation includes experimental testing that includes three pair of specimens subjected to shear loading to evaluate their shear strength capacity, strain, and connection flexibility behaviour as well as the resulting crack propagation throughout the test. The test was verified through Acoustic Emission (AE) technique using Energy (eu) parameter. The proposed sample tested shows a significant improvement compared to the control sample with respect to maximum shear strength, however it displays a brittle behaviour by developing multiple cracks along the connection interface and having a significant shear failure at the end of the test. The findings of this study will contribute to a better understanding of the behavior of dapped wet connection and provide preliminary guidance for their design in precast concrete wall panels.

Keywords: Dapped connection; Industrialised Building System; Precast wall panel; Recycled concrete aggregate; Push-off shear test; Acoustic Emission technique

The connection between two wall panels is the weakest part of the wall system and becomes the crucial point of failure. This paper presents the behaviour of two proposed types of wall-to-wall connections subjected to uniformly distributed load until failure, dapped wet and lightly vertically reinforced dapped wet connections. A total of twelve wall panels were prepared and constructed as six wall-to-wall connections, with three connections for each type. The acoustic emission (AE), maximum load (P_max), strain and deflection characteristics were analysed and discussed to determine the behaviour of each wall-to-wall connection. The occurrence of cracks on the walls during the tests was also observed. The results showed that the P_max for the wet and lightly vertically reinforced wall-to-wall connections of dapped concrete were 164.37 kN and 138.44 kN, respectively. From the distribution of AE, the highest energy was determined for the lightly vertically reinforced wall-to-wall connection, at 18000 eu. From the AE activity mapped on the crack pattern, it was observed that most AE activities occurred at the top of the wall, which corresponded strongly with the occurrence of cracks at the wall connection surface. Vertical cracks occurred in the connection areas, propagating from the top to the bottom. The major benefit of this study is the proposal for a new type of vertical wall-to-wall connection that can be used in prefabricated wall panel systems in industrialised building systems.

Keywords: Dapped connections; Industrialised Building System; precast wall panel; recycled concrete aggregate; uniformly distributed load; Acoustic Emission technique

The use of recycled concrete aggregate (RCA) in the production of concrete structures in Malaysia is minimal and does not match the amount of recycled concrete waste produced during a similar period. Moreover, there is a growing need to shorten the construction period, which necessitates the use of lighter concrete materials to produce lighter material with a minimal strength that able to act as part of the structures. Hence, this study aims to analyse the physical and mechanical properties of control strength lightweight mortar (CSLM) made from RCA and expanded perlite (EPA). The nominal size of crushed RCA and EPA was 4.75 mm, like the natural sand (NA) used. Several ratios of RCA, NFA, and EPA (fine aggregate) were employed to determine the optimal ratio of fine aggregate to cement. The CSLM underwent testing for its uniaxial compressive strength at 3, 7, and 28 days, while flexural strength was tested only at 28 days. It is found that the ideal proportion of RCA and EPA in CLSM is 40% and 20% of the total fine aggregate content, respectively. Meanwhile, the optimal mix ratio for CSLM consists of 40% RCA, 40% NFA, and 20% EPA. Hence, it can be concluded that the presence of residual mortar in RCA increased the water absorption rate, resulting in lower compressive and flexural strength when higher proportions of RCA and EPA were used. Studying CLSM using RCA and EPA offers the benefit of creating more sustainable construction materials by reducing waste and conserving natural resources.

Keywords: Recycle concrete aggregate; lightweight cement mortar; compressive strength; flexural strength; expanded perlite

The increasing depletion of natural resources and the environmental impact of conventional construction practices necessitate the exploration of sustainable alternatives in the construction industry. One promising approach is the use of recycled concrete aggregate (RCA) as a partial replacement for natural fine aggregates in concrete production. However, the performance of RCA in structural applications remains a critical concern, particularly regarding its impact on the mechanical properties of concrete. This study investigates the effects of RCA on the structural performance of wall panels subjected to uniformly distributed loads, with a focus on fresh and hardened properties. Wall panels with dimensions of 1000 mm x 480 mm x 120 mm were produced with RCA replacing 0% and 50% of the natural fine aggregate. The samples were labelled as control (SW120UC) and RCA (SW120U) samples, respectively. In terms of fresh properties, the workability of the control mortar (SW120UC) with 0% RCA was 57%, while the mortar with 50% RCA (SW120U) exhibited a workability of 56%. For hardened properties, the compressive strength of the control cubes (SW120UC) at 28 days was 10.21 MPa, whereas the cubes containing 50% RCA (SW120U) achieved a compressive strength of 16.52 MPa. The maximum load capacity of the RCA wall panels (SW120U) was 90 kN with a stress of 1.6 MPa, compared to 70 kN and 1.2 MPa for the control panels (SW120UC). Furthermore, the highest load versus deflection analysis revealed that SW120U with RCA reached a maximum load of 90 kN with a vertical deflection of 1.49 mm, whereas SW120UC with 0% RCA exhibited a maximum load of 50 kN and a deflection of 0.6 mm. These results demonstrate that RCA can significantly enhance the structural performance of concrete wall panels by improving compressive strength and load-bearing capacity while maintaining acceptable workability.

Keywords: Mortar; recycled concrete aggregate; wall panel; compressive strength

The calculation of minimum determinant plays a crucial role in fulfilling the determinant criterion of a certain code design in space time trellis code. In the heuristic optimization of code construction, the minimum determinant is derived via a variant of the branch and bound algorithm. Although the algorithm is relatively efficient, it is not optimized in terms of the pruning strategy. Search space is pruned when the upper bound is exceeded. The upper bound restricts the area of the search space by acting as a minimize agent. No attempt is made on discerning the potential of different structures within the search space. This paper proposes a new pruning approach to improve the computational efficiency of finding the minimum determinant for a particular genera-tor matrix G. It builds upon the idea of minimal complete cycles. They are the smallest paths that begin and ends with zero. By capitalizing on the minimum complete cycle of the search tree, the structure with the highest potential in the search space can be identified. Consequently, it helps the search process to differentiate subtrees in their capacity of yielding a solution. Search can be focused on a certain subtree while others are pruned altogether. This enables approximately 45% reduction of the overall spatial and temporal cost. Despite its potential, the pruning method is inherently probabilistic. There is a 0.0357 risk that it could provide an erroneous minimum determinant.

Keywords: STTC; code design; determinant criterion; minimum determinant; search algorithm

The Green Campus represents an educational institution that prioritizes environmental sustainability and integrates green practices into its infrastructure, policies, and culture. The Green Campus aims to reduce environmental impact by conserving resources, minimizing waste, promoting renewable energy, and improving air and water quality. However, in the pursuit of Green Campus sustainability, there are still several issues that need attention and immediate action. Therefore, three objectives have been set in this study: to identify the level of awareness and practices of Green Campus among the Polytechnic community, to assess the factors influencing the level of awareness of the Polytechnic community towards Green Campus practices, and to develop a Green Campus action plan as a guideline for Malaysian Polytechnics. This study will use a questionnaire as the research instrument. Seven Polytechnics involved in the 2022 UI Green Metric assessment have been selected as the study sample. The findings show that the level of awareness and practices of Green Campus is still at a moderate level among the Polytechnic community. Meanwhile, 17 factors influencing awareness and practices of Green Campus among the Polytechnic community have been listed. This study has also successfully developed a Green Campus action plan as a guideline for Malaysian Polytechnics in preserving the Green Campus. In conclusion, the results of this study can be used as a reference by Malaysian Polytechnics to improve the implementation of the Green Campus.

Keywords: environmental sustainability; green campus; green practices; Malaysia polytechnic

Water footprint (WF) can be used as a comprehensive indicator of the use of freshwater resources and as a measurable metric to determine the amount of water used per unit of crop. Rice cultivation uses large amounts of water to increase crop yields. Since water is the most important component for rice cultivation, it is important to understand how much water is used during agriculture and the quantity of water in the rice crop per ton of product. The aim of this study is to evaluate the water footprint of rice crops in the Muda area regulated by the Muda Agricultural Development Board, for five consecutive years from 2018 to 2022. CROPWAT 8.0 computer programming, meteorological data such as (rainfall, temperature, speed wind, relative humidity, and solar radiation) and rice crop yield data are used to estimate water evapotranspiration (ET) for the blue and green water components, and continue the water footprint calculation. Methodological framework according to crop water requirements options based on the water footprint assessment manual. The water footprint calculation focuses on the blue, green, and grey water footprint components. The findings of the study show that the three components of the water footprint differ significantly from each other. In the Muda area, the average value of the green water footprint (WFgreen ) is 1102.3 m3/ton (56.6 %) higher than the blue water footprint (WFblue ) which is 506.4 m3/ton (26 %), and the value of the grey water footprint (WFgrey ) is 337.4 m3/ton (17.3 %). 57 % green water footprint indicates that there is enough rain to support rice growth. Water footprint assessment provides more comprehensive understanding of the environmental sustainability of rice crops. Data from the assessment can be used to formulate policies that promote sustainable rice cultivation and the best cultivation methods.

Keywords : Water footprint; CROPWAT 8.0 programming; rice cultivation; sustainability; Muda area

The increasing population and modern lifestyle demand have caused the increase in waste sludge production gradually at the same time causing environmental pollution. Thus, the idea of reusing this waste sludge emerges as an alternative way of reusing it to create a product instead of disposing it. The Naphthalene sludge, a by-product obtained from the production of superplasticizer, also known as concrete admixture, is used in this study as an additive in concrete. Concrete was produced with 0%, 1%, 2% and 3% additive of the naphthalene sludge and the workability and strength of mortar and concrete were studied to investigate the effect of the waste sludge on concrete. Samples for compressive strength test were prepared with fixed Water-cement (W/C) ratio of 0.50 and cured for 7 and 28 days. The results showed an increase of concrete and mortar strength when the waste sludge addition is increased. 3% of Naphthalene sludge additive shows the highest concrete strength based on the 28 days strength and obtained the best workability among the control sample and the other 1% and 2% of additive. By adopting sustainable practices in waste management and innovation can mitigate adverse impacts while supporting global sustainability development goals (SDG) 2030.

Keywords: Concrete waste; concrete strength; workability; green concrete; waste innovation; SDG2030

Cold-formed steel (CFS) is increasingly being used in modern buildings owing to its lightweight, recyclable nature and material usage efficiency aligning with sustainable practices. Built-up CFS sections have garnered significant attention owing to their increasing application in modern construction. These thin-walled CFS sections are prone to low buckling resistance, limiting their application in tall buildings under extreme loading conditions. This paper review comprehensively the buckling behaviour and structural stability of various CFS built-up configurations of face-to-face, back-to-back non-gapped and back-to-back gapped configurations. The findings show that built-up sections enhance structural performance by reducing local, distortional, and global buckling compared with single sections. Fasteners and stiffeners are crucial for improving the performance by optimising the fastener spacing and the inclusion of stiffeners significantly enhances structural stability. These modifications enhance both the structural axial and flexural performances by improving the buckling resistance under extreme loads. Current design standards often inadequately address buckling complexities and necessitate updates to fully leverage CFS’s structural potential. The back-to-back gapped configuration stands out for its superior constructibility particularly in truss systems, owing to its ease of assembly, adaptability to buckling challenges and improved lateral stability. Innovative design improvements and updated guidelines are required to enhance CFS applications in sustainable and resilient structural systems.

Keywords: Built-up section; back-to-back section; closed section; Cold-formed steel (CFS); open section

An Ambulatory Surgical Center (ASC), also known as an outpatient surgery center, is a medical facility that provides same-day surgical procedures to patients who do not require an overnight stay in a hospital. ASCs are equipped with state-of-the-art medical equipment and staffed by highly trained healthcare professionals, including surgeons, anaesthesiologists and nurses. There are many areas along the river where people do not have easy access to any surgery. They have to go far to get this service, for which they do not even take the service. This research is for them. This research will ensure their basic medical services. The contribution of this research, this world-class surgical ship goes to ensure the basic medical needs of poor people in remote areas where good healthcare is not available. Another great contribution that will surprise the world is that no conventional fuel is needed to ensure this healthcare service. So undoubtedly this research has a great contribution in the global energy crisis. To ensure efficient ambulatory surgical center (ASC) ship, conducting site assessment, sizing the hybrid system appropriately, selecting the right components, improving hybrid energy system design, implement intelligent system is important. And these are the scope of our research. A detailed analysis of all possible aspects has shown that using intelligent hybrid energy ships instead of conventional ships improves the quality of service. Long lasting service is achieved with low energy consumption, sustainability and no pollution even without compromising performance. In this research details of ASC will be critically discussed.

Keywords: Hybrid energy system; Ambulatory Surgical Center Ship; intelligent system; outpatient surgery center; efficient system

Traditional teaching approaches are often criticized for their limited effectiveness, especially in helping students improve their academic performance. Cooperative learning, where students interact in small groups to meet learning objectives, has been proposed as a more effective alternative approach. The purpose of this research is to evaluate the impact of cooperative learning on students’ achievement in the Vector Calculus (VC) course by comparing two groups: the experimental group that uses the cooperative learning approach and the control group taught using traditional methods. Data were collected through pre-tests and post-tests for both groups. An independent t-test analysis was conducted to test the study’s hypothesis. The t-test results for the pre-test showed no significant difference between the experimental group (M = 52.90, SD = 2.834) and the control group (M = 57.15, SD = 6.746), p = 0.5001, indicating that students from both groups had similar initial performance levels. However, the t-test results for the post-test revealed a significant difference between the two groups, with the experimental group using cooperative learning showing a marked performance improvement compared to the control group. Additionally, the comparison between the pre-test and post-test in the experimental group also showed a significant increase in student achievement. Conversely, the control group showed a significant decline in performance from the pre-test to the post-test, indicating that traditional teaching methods may be less effective in this course. In conclusion, the findings of this study suggest that the cooperative learning approach has a positive and significant impact on student achievement in the VC course compared to traditional teaching methods. Therefore, cooperative learning is recommended to improve students’ academic performance. Educators may consider incorporating group activities, collaborative discussions, and joint problemsolving to optimize the effectiveness of this approach in their teaching.

Keywords: Cooperative learning; Traditional teaching method; Student achievement; Vector Calculus course; Inferential analysis

Microbial Electrochemical Sensor (MES) is classified as a self-powered electrochemical biosensor and utilising biofilm electrode used as a sensor. Conventional techniques such as ion chromatography (IC), highperformance liquid chromatography (HPLC), and chemical oxygen demand (COD) require large, expensive, and non-portable equipment. Therefore, MES has gained significant attention due to its advantages, including low cost, easy operation, and portability. Stainless steel (SS404L) is widely used in various applications but exhibits lower biocompatibility compared to carbon-based materials when used as an anode. This MES is constructed using modified electrodes through techniques such as carbon coating, electrochemical reduction, flame oxidation, and graphene coating. A nutrient medium stock is periodically supplied daily to enrich the electroactive microbes and maintain the biosensor’s performance at a stable level. Samples are collected and analyzed during pollutant testing to determine pH, conductivity, IC, and COD values. These parameter values are correlated with MES signal data to assess each biosensor’s performance in terms of reaction rate. FESEM-EDX and RAMAN analysis indicated an increase in O content from 2.4% to 19.9% for flame oxidation. For carbon and graphene coatings, carbon content increased from 4.1-9.1% to 48.4-78.6%. The carbon coating exhibited an R² value of 0.7023 for tests using 4-nitrophenol. Meanwhile, for potassium nitrate, the graphene coating demonstrated the highest R² value of 0.8785. A higher R² value indicates a stronger correlation and suggests better performance in electrode modification within MES. This highlights the significance of MES results in water quality monitoring, which can be understood and applied more effectively.

Keywords: Microbial Electrochemical sensor; surface modification; flame oxidation; carbon powder coating; stainless steel SS304L

Cooling powder is a traditional local cosmetic product produced from natural fermentation of rice. This product has been passed down until today due to its beneficial properties and is believed to have a cooling effect on the user. In current market, this product is still being sell in its traditional form which is in the form of powder and beads which are difficult to use. At the same time, there are concerns regarding safety talc-based cosmetics due to its potential contamination with asbestos, a toxic mineral. Therefore, this study is conducted to modernize this increasingly forgotten traditional product into a compact powder and replace the talc composition with cooling powder. Binding agents and oil absorbing agents are added to produce better quality of compact powder. The objective of this study is to determine the best composition of powder, binding agent and oil absorbing agent for compact powder formulations by using Response Surface Methodology (RSM), where Central Composite Design (CCD) is utilized. The cooling powder composition studied for the compact powder formulation are 50%, 55% and 60%. Meanwhile, kaolin is added as oil absorbing agent with compositions of 20%, 25% and 30%. Virgin coconut oil is added as binding agent at varied composition of 5%, 7.5% and 10%. Two types of drop tests are carried out to investigate the durability of the compact powder formulation, which are weight and height drop tests. Oil absorption capacity test is performed to evaluate the effectiveness of the compact powder formulations in absorbing oil.

Keywords: Green cosmetics; cooling powder; compact powder; rice fermentation; RSM

Research in production of bioethanol has been accelerating since the world faced depleting fossil fuels. To obtain high ethanol yield and fermentation rate, response surface methodology (RSM) was applied to study the effect of medium and alginate-ST1 yeast cell beads toward production of bioethanol using local yeast strain called ST1. Bioethanol was produced by immobilized ST1 yeast grown in local brown sugar (LBS) using shake flask mode at 30˚C for 6 hour and the effect of LBS concentrations, ratio of alginate (ST1) beads to the medium volumes and the beads size were investigated. Firstly, 2³ full factorial design (first order model) was carried out to identify the significant effect prior to second-order model; central composite design (CCD) can be proposed. The first order model analysis showed that the selected parameters are significant in glucose utilization and bioethanol production. The total bioethanol production was 5.30 g/L under optimum conditions, an increase of 14.16% compared to the production before optimization, which was 4.73 g/L. The CCD results showed that the optimum conditions for bioethanol production were at a ratio of 125 g/L LBS for LBS concentration, 0.47 for the ratio of alginate beads to medium volume, and 0.33 cm for alginate bead size. Overall, this study demonstrated the successful immobilization of ST1 yeasts in alginate, which improved the effectiveness and productivity of bioethanol production. This approach offers a more sustainable solution, as the yeast cells can be reused, thereby shortening the harvesting process and contributing to a more efficient bioethanol production system.

Keywords: Bioethanol; immobilized yeast; calcium alginate; response surface methodology

The current study aimed to enhance dye decolorization by integrating adsorption and enzymatic degradation processes using laccase immobilized in silica microparticles. In-situ immobilization of laccase was achieved via solgel technique through two-step (acid–base catalyst) methods, employing hydrolysis and condensation of tetraethyl orthosilicate (TEOS) as the precursor. Various parameters, including pH, temperature, dosage loading, and reaction time, were meticulously examined to optimize the process. The findings revealed that combination of immobilized laccase significantly improved the decolorization of malachite green dye by over 20% compared to single adsorption using silica alone. The highest decolorization efficiency of 94.21% was attained through the synergistic effect of adsorption and enzymatic degradation facilitated by immobilized laccase in silica. This immobilization not only enhanced the enzyme’s stability but also made the decolorization process more efficient. The study underscores the potential of silica-immobilized laccase as a powerful decolorizing agent, which could also be applied to the degradation of other contaminants in wastewater. This innovative approach highlights the advantages of combining adsorption with enzymatic degradation, offering a promising solution for treating dye-laden industrial effluents. The enhanced stability and efficiency of the immobilized enzyme demonstrates a significant advancement in the field of bioremediation, paving the way for more effective and eco-friendly methods to address water pollution.

Keywords: Dye removal; adsorption; enzymatic degradation; laccase; silica microparticle

Street art, which originally stems from graffiti, has evolved into a powerful medium that has a significant impact on the cultural and physical landscape of heritage cities. “Literature Review on the Physical Characteristics of Heritage Cities from the Perspective of Street Art Design,” will explore the various roles played by street art in urban environments. The primary aim of this research is to examine the influence of street art on the physical and cultural character of heritage cities. Through a comprehensive literature review and case study analysis, this research highlights how street art contributes to the aesthetic transformation of urban areas, preservation of cultural heritage, and socio-economic development. The study also explores the evolution of street art from acts of rebellion to a recognized form of public art that interacts with its environment and connects with local communities. It emphasizes the potential of street art to beautify cities, express culture, and build community. By highlighting the importance of street art in heritage cities, the research examines how various forms of graffiti, murals, stencils, posters, and 3D installations interact with public spaces and impact the physical character of heritage cities. Findings from the literature review indicate the transformative potential of street art in heritage cities. It plays a crucial role in the aesthetic transformation of urban areas, cultural preservation, revitalization, social and environmental awareness, as well as economic development such as attracting tourists. Additionally, it offers recommendations for sustainable practices and community engagement to ensure the continuity and relevance of street art projects.

Keywords: Street art; physical character; sense of place; cultural heritage; aesthetic value

This study focuses on developing and validating an instrument to measure the readiness for Internet of Things (IoT) integration in fire detection systems for residential housing types. The main objective is to develop a valid and reliable survey instrument to assess users’ readiness to accept and use IoT technology in the context of home fire safety. The research methodology involves a combination of the Technology Readiness Index (TRI) Theory and the Technology Acceptance Model (TAM) as the theoretical basis for the development of instrument items. This process was followed by content validation involving six expert panel members appointed in the field of fire safety. Survey questions were distributed to experts via email. These experts assessed the proposed items’ appropriateness, clarity, and relevance. The initial instrument consisted of 45 items covering the main dimensions of TRI (optimism, innovation, discomfort, insecurity), TAM constructs (perceived usefulness, perceived ease of use, and behavioral intention), and Readiness to use IoT for fire detection at home. The findings were analyzed using the Content Validity Ratio (CVR) and Content Validity Index (CVI) methods. Through the content validation process, 7 items were revised or filtered to produce a final instrument with 38 items. Findings show that the developed instrument has good content validity, with a satisfactory Content Validity Ratio (CVR) and Content Validity Index (CVI). Reliability analysis indicates high internal consistency across all dimensions of the instrument. This study contributes to the literature by providing a validated instrument to measure IoT integration readiness in residential fire detection systems. This instrument can be used by researchers, policymakers, and industry professionals to assess and predict IoT technology readiness in the context of home fire safety.

Keywords: Internet of Things (IoT); fire detection systems; technology readiness; instrument validation; Technology Readiness Index (TRI); Technology Acceptance Model (TAM)

Coastal erosion is a global problem affecting almost every country due to natural and human factors. Malaysia has a coastal zone of 4,809 kilometres, and it is estimated that the rate of coastal erosion has exceeded 30% of the length of the coastline. The problem of coastal erosion is becoming more critical as the coastline is a hotspot for humans to carry out various activities, and development activities are unproductive. Settlements were also destroyed by the sea and had to be displaced due to severe erosion in various countries. Various national studies have found that the most critical impact of coastal erosion is on property. Therefore, the objective of the research is to identify the effects of coastal erosion and, subsequently, to specialize the effects of coastal erosion on the market value of the property. Various findings of previous studies have shown that the negative impact of coastal erosion involves residential properties with a percentage decrease in the market value of property at a minimum rate of 1% to a maximum of 52%. The research uses qualitative methods as a research method for data collection. The qualitative data used is secondary data in the form of document analysis. The research begins by describing the issues and scenarios of coastal erosion, then a literature review is discussed consisting of coastal erosion information, coastal erosion effects, and the effects of coastal erosion on the market value of the property. This research is important for the benefits, understanding, and technical knowledge of the impact of coastal erosion on property value to property owners, real estate industry professionals, and other stakeholders. Further research is recommended to examine the factors influencing the market value of coastal erosion properties and identify the extent of the volatility of the market value of coastal erosion and non-erosion properties.

Keywords: Coastal erosion, effects of coastal erosion, market value, property

The design of traditional Malay houses is influenced by Islamic values in aspects of privacy, user comfort, and environmental sustainability. The problem in the context of living space arrangements today is less adaptation to the local climate and culture of family and community that is emphasized in Islam. The objective of this study is to understand how Islamic principles of user comfort, privacy and sustainability are applied in the design of traditional Malay houses and to evaluate their effectiveness. This study was conducted on several traditional houses at Universiti Putra Malaysia – Rumah Penghulu Ismail bin Khatib Bakar, Rumah Haji Wan Muda Haji Wan Hassan, Rumah Perak Uda Noh B. Kandar Jaafar, and Rumah Datuk Raja Diwangsa Muhammad Yunus bin Jabar, as well as several other traditional houses. The houses were chosen to represent each different state as they have different regional cultural values and microclimates that make the architectural design different from each other. Through data analysis obtained from field observations, questionnaires, literature reviews, and expert interviews, the findings show that traditional Malay houses are designed to ensure privacy through separate entrances for men and women and the arrangement of sleeping areas. User comfort is ensured with natural ventilation and the use of high-quality materials suitable for the local climate. Additionally, the approach to environmental sustainability in the design of traditional Malay houses reflects adherence to Islamic teachings. In conclusion, the principles of simplicity, privacy, and environmental sustainability not only contribute to the well-being of the occupants but also benefit the environment. This study emphasizes the importance of preserving traditional values in Malay house architecture for the well-being of society and environmental sustainability.

Keywords: Traditional Malay architecture; Islamic principles; comfort; privacy; sustainability

Transit housing for young people who have just started work is a housing concept that provides temporary accommodation and support services to individuals in the early stages of their careers. In Malaysia, the priority of housing for the youth is an important issue because the price of housing units nowadays burdens young people who have just started working to get an affordable house or room according to their ability. They face current challenges, including moving away from their hometown to get work and looking for new job opportunities in big cities like Kuala Lumpur. The youth is a valuable asset to the economic growth of the country. Therefore, it is very important that a transit house can be developed before they can buy a new house. Data was collected from a questionnaire survey answered by 100 local university graduates and young people who have just started working around Selangor and Kuala Lumpur. The results of the study on the needs and requirements of transit housing space can provide an important contribution to the development of transit housing in Malaysia. This research can identify the wants and needs of the transit house chosen by the youth which involves the required spaces, types of rooms, and types of programs in transit housing in Malaysia.

Keywords: Transitional housing; young adults; affordable

The answer to the question of national architectural identity requires continuous strategies and efforts from various parties covering various architectural typologies. This study focuses on the development of a criterion for the application of architectural element design with national identity characters to skyscrapers that are classified as tall buildings above 150 metres. The PETRONAS Twin Towers building in Kuala Lumpur was selected as a study sample in the development of the criteria for the application of the national architectural identity element using the case study method. There are two research objectives to be achieved through this study, namely to identify the universal value in the formation of national architectural identity and to propose the value of the identity as one of the criteria in the application of national identity elements in the design of skyscrapers in Malaysia. This research debate is carried out based on nine basic principles of vernacular architectural identity formation. The principle is a basic criterion in the formation of the identity of early civilization at the global level that reflect the concept of the nation-state. The nine principles in question are religion, architectural language, culture, economy, architectural evolution, geography, politics, art and technology. The findings of this study are in the form of a table of criteria for the application of national architectural identity elements based on five design development factors obtained from the study building. The intended factors are site and design, construction methods, symbols, material surfaces and the public realm.

Keywords: National architectural identity; skyscraper; application criteria

Homeless children are a group that cannot be marginalized and have the right to get formal education like other normal children. The issue of dropping out of education for homeless children is seen to be increasing from time to time due to the factors of poverty and also the collapse of family institutions. Sekolah Bimbingan Jalinan Kasih (SBJK) is a special school that accommodates street children around Chow Kit where it provides access to education in terms of academics and skills to them and gives homeless children the opportunity to shape their career path in the future. The purpose of this study is to see how effective the learning space provided by the government is for homeless children at Jalinan Kasih Guidance School (SBJK) Kuala Lumpur. This study uses quantitative methods and qualitative methods where questionnaires and in-depth interviews are used. For the quantitative method, a set of questionnaires on space needs and learning facilities as well as basic needs will be submitted to a sample. This set of questions will be answered by 30 respondents consisting of schools and also Non-Governmental Organizations (NGOs) involved in providing support. While for the qualitative method, an interview session with 6 students consisting of 2 preschool students, 2 primary school and 2 high school students will be conducted to obtain more detailed information and the observation method has also been implemented. The results of the study show that the Jalinan Kasih Guidance School has provided sufficient learning space in terms of needs and facilities as well as providing comfort to homeless children. However, the majority thinks that the needs and facilities provided can still be improved by providing accommodation facilities and school grounds for leisure activities. Therefore, the discussion of this paper has discussed the efforts and initiatives that have been implemented by the government in helping homeless children get access to proper education, and the study can also be improved if it can compare the learning space provided by the school and NGOs in overcoming the problem of homeless children dropping out of education.

Keywords: Effectiveness; learning space; child homelessness; school

It is important to maintain the interior thermal comfort of a mosque to ensure visitors are comfortable for worshipping activities. Usually, traditional mosques use passive design strategies to maintain interior thermal comfort. However, many modern mosques depend on air conditioning to ensure indoor thermal comfort. This leads to high energy use and being not sustainable. Therefore, an understanding of passive design is important to reduce dependency on air conditioners that require high energy. The objective of this study is to investigae the internal temperature of a selected mosque that uses natural ventilation as a strategy to maintain the indoor thermal comfort. The main research method is to measure the temperature and the humidity of the selected mosque. The main method is supported by literature review study and site observation several selected mosques. The selested mosque for measurement is the Universiti Kebangsaan Malaysia (UKM) Mosque. Equipment calibration process is completed prior to measurement to ensure it is accurate. Observation at site found that the UKM Mosque uses various design strategies to achieve internal thermal comfort such as having large overflow spaces as well as high and open ceiling spaces. The study found that the temperaturse inside the mosque are between 28.9℃ and 31.7℃. The study also found that the prayer hall on the ground floor is cooler than the main prayer hall on the first floor. The recorded range of temperature also proved that the indoor thermal comfort of the mosque can be achieved by providing ceiling fans with appropriate wind speeds. The findings show that the mosque’s passive design strategies successfully maintain the indoor thermal comfort of the mosque without the need for air conditioning system. It is hoped that the findings of this study can be used as a general reference by designers in designing sustainable modern mosques.

Keywords: Universiti Kebangsaan Malaysia; mosque; temperature; thermal comfort

Uncertainties in powder spreading in powder bed-based additive manufacturing (AM) have posed challenges in the quality and repeatability aspects of manufactured parts. These challenges result in high porosity due to voids existing between the powder bed particles. This work focuses on identifying the uncertainty induced by particle size distribution (PSD) on powder flowability using SS316L as a model material. Various sizes of particles, ranging from 10 µm to 100 µm, as well as spherical and satellite-shaped particles with a bimodal ratio of 70:30, were analyzed. The tapped density, apparent density, and Hausner ratio of each sample will be determined using USP 616. Smaller particle sizes have been shown to reduce both bulk and apparent density. Meanwhile, the shapes of particles also contribute to the packing ability between the powder particles. Satellite powder has been proven to increase the diameter of the powder, consequently enhancing the bulking density of the powder particles. Moreover, bimodal particles have been shown to increase both bulk and tapped density, whereas smaller powder is not able to fill the voids that exist between the larger particles. However, the bulk density decreases as the size ratio between the powder particles increases, indicating that smaller powder is capable of filling the gaps between the particles. When comparing the powder particles in terms of Hausner ratio value, bimodal particles have been shown to cause the poorest flowability with a value of 1.19856. This is due to the fact that the smaller particles between the larger particles increase the friction between the powders. Therefore, this study illustrates how particle size and shape influence powder packing densities, which is crucial for optimizing material design and processing techniques.

Keywords: Powder packing density; tapped density; bulk density; loosening effect; satellites; spherical powder

Wood has played a crucial role in the field of architecture, prototyping, and engineering, owing to its aesthetic appeal and specific mechanical properties tailored for diverse applications. The application 3D printing has facilitated the replication of natural materials like wood, enhancing both their visual and mechanical attributes. This research aims to investigate the mechanical properties of 3D printed PolyWood^TM materials and compare them with those of real wood composites. The mechanical property assessments conducted on PolyWood^TM samples encompass tensile, flexural, and compression tests. The obtained results are analyzed and compared with data from literature readings on real wood composites. The average tensile strength of PolyWoodTM material is 20.31 MPa, the flexural strength is 31.36 MPa, and the compression strength reaches up to 21.70 MPa. In comparison with real wood composites, the PolyWood^TM sample exhibits inferior performance in most mechanical properties. Regarding tensile strength, the performance of the material is comparable to other composite but is almost 50% lower than the Pure PLA performance. However, in term of Young’s Modulus, a significant difference is observed across all references, indicating more flexibility and larger elastic deformation under a given load for PolyWood^TM material. The differences on flexural strength were not obvious, with one research study showing lower strength. Finally, the compressive performance of real wood composites and pure PLA demonstrates superior resistance and strength when contrasted with PolyWood^TM materials.

Keywords: Fused Deposition Modeling (FDM); PolyWood^TM; wood polymer composite

The occurrence of earthquake events has caused numerous causalities and economic losses within the construction industry in the past and present years. However, people have insufficient knowledge and awareness of the impact of earthquakes, especially in understanding the seismic response of complex underground construction industries such as tunneling. Careful consideration of the impact of earthquakes on such structures is crucial due to previous experiences of catastrophic earthquake events that severely damaged underground structures. This study aims to investigate the effect of different soil material properties (i.e., soft soil and rock) on the seismic response of circular tunnels under increasing earthquake ground motion using simplified pseudo-static analysis, while simultaneously emphasizing the shortcomings of conventional closed-form solutions. To achieve this, a two-dimensional (2D) simplified pseudo-static analysis of a soil-tunnel model embedded at 20m depth was investigated under increasing levels of seismic intensity at the transverse direction of the tunnel axis using PLAXIS 2D software. The tunnel is modeled as a circular shape with a 0.5m thick tunnel lining embedded at a depth of 20 m from the ground surface in two different types of soil profiles i.e. soft soil and rock. The soil is treated as a single-phase medium without excess pore pressure. The six seismic intensities of peak ground acceleration (PGA) ranging from 0.1g to 0.6g were considered in this study. For validation purposes, the numerical results of pseudo-static analyses were verified with the analytical closed-form solution using Wang’s method 1993. The findings indicate that the tunnel embedded in soft soil experienced maximum structural forces for bending moments and axial forces compared to rock. Results denoted that the seismic responses of the tunnel increased with the increment of earthquake magnitude and its epicenter. Notably, the results of analytical methods seemed to be underestimated compared to numerical analyses.

Keywords: Seismic response; tunnels; soft soil; rock; pseudo-static analysis

Maximum Power Point Tracking (MPPT) is a crucial strategy for maximizing energy extraction from Thermoelectric Generators (TEGs). Various MPPT techniques, such as Interval Type 2 Fuzzy Logic Controller (IT2FLC), Extremum Seeking Control (ESC), and Perturb and Observe (P&O), have been developed to achieve optimal power output from TEG systems. Among these methods, the P&O technique stands out due to its ease of implementation and control scheme, cost-effectiveness, and high output power. This paper proposes a design that integrates TEG arrays, boost converters, and the P&O algorithm to optimize power extraction from TEG systems. The performance of the system utilizing the P&O based MPPT technique is compared to the system without MPPT under the same operating conditions, highlighting the significant of MPPT in enhancing TEG efficiency. The results demonstrate that the P&O algorithm effective increases the efficiency of MPPT in TEG systems. This study was conducted using the MATLAB/Simulink environment.

Keywords: Thermoelectric generator; MPPT; P&O; DC-DC boost converter; MATLAB/Simulink

This study examined the use of stir casting to create an aluminum-nanoscale boron carbide composite. Following the sample’s solidification, mechanical and physical tests are carried out to determine the density and hardness. Tafel polarization in a 3.5% NaCl solution was utilized to determine the composite’s corrosion behavior, and tensile strength and hardness characterization techniques were employed to determine its mechanical characteristics. After the stir casting process, the surface morphology of the metal and the dispersion of boron carbide particles on the matrix were examined using a field emission scanning electron microscope (SEM). The obtained powders and matrix samples were examined using X-ray diffraction (XRD) analysis to determine the phase and if reinforcement particles (B₄C) were present in the composite samples. The mechanical, microstructural, and corrosion investigations were used to evaluate the performance of the composites. The homogeneous distribution of the reinforcing particle was observed by the inspection of micrographs. The results showed that the corrosion rate of the aluminium matrix composite was lower than that of the base alloy in a 3.5% NaCl solution. Simultaneously, the composite’s corrosion rates escalated as the B₄C concentration in the aluminum matrix grew. Hardness investigation has demonstrated that an increase of B₄C content in the aluminium matrix enhanced the hardness rating. In the tensile test, the composite containing 0.8 weight percent B₄C achieved a maximum strength of 149.95 MPa, which was roughly 48.64 MPa (32%) greater than the basic alloy.

Keywords: Aluminium matrix composite; nano size boron carbide; corrosion; hardness and tensile test

Bunion or Hallux Valgus is a bony bump at the joint connecting the foot with the big toe. Bunions cause pain and discomfort especially when wearing shoes. Choosing appropriate footwear is not a real solution because it is limited to selecting open-toed shoes to avoid pressure on this area. Commercial insoles are generally available in standard sizes, whereas this phenomenon varies from one individual to another. Therefore, the objective of this study is to suggest bunion pads design with custom designs according to individual needs and then fabricate them using economical methods for small-scale production, i.e., additive manufacturing. A subject chosen in this study experiences bunion problems at the initial formation stage. Interview methods and anthropometric data collection on the patient’s foot using vernier calipers and an anthropometer were conducted before designing the bunion pad according to the subject’s size and foot shape. Fabrication was carried out using a 3D printing method called Fused Deposition Modeling (FDM), and the material used was Thermoplastic Polyurethane (TPU). Pressure distribution on the subject’s foot was taken without wearing the bunion pad using a Tactilus pressure mapping system to compare areas with high pressure and ensure that the design could provide comfort to the subject. The design of this bunion pad is divided into two parts, namely the thumb liner and the liner on the metatarsal (MTP) region. In the interview, after wearing the bunion pad with a 60% infill density, which was specifically designed to support pressure on the subjects, users reported improved comfort.

Keywords: Bunion; anthropometric; foot; Fused Deposition Modelling (FDM)

Composting is a sustainable practice that uses the organic waste as the nutrient-rich compost, which offers numerous benefits in agriculture while improving soil fertility and enhances plant growth. Organic fertilisers are increasingly recognized for their potential to enhance crops productivity while at the same time have less impacts towards the environment. The aim for this study was to evaluate the effects on the different application of fertilisers on the growth and yield of the Roselle plant (Hibiscus sabdariffa) by evaluating on the plant growth parameters. This study is focused on the plant growth and determination of nitrogen (N), phosphorus (P) and potassium (K) uptake of the plant. The plants were divided into four (4) different treatments with one being the control. Among the plant growth metrics examined in this study are plant height, leaf count, and Roselle yield. After 49 days of observation, the plant height averaged at 178 mm, with 16 leaves produced across all treatments. Roselle that grown under combination of soil, fertiliser with compost (P3), and soil with fertiliser only (P4) produced the most number of fruit (8 fruits/plant). In addition, the highest leaves count (45 leaves/plant) contributed from Roselle under soil with fertiliser only (P4). It is observed that the Roselle with organic fertiliser treatment have low significant improvement in plant growth as compared to the plants in other treatments. The findings of this study showed that food waste can be applied in composting to promote plant growth ecologically responsible farming practices and improve plant development and output. The benefits of compost may be more noticeable over a longer period and in combination with other soil management practices.

Keywords: NPK uptake; organic fertiliser; plant growth; roselle

The contamination of water by heavy metals poses significant environmental risks, impacting ecosystems and human well-being. In response, this study investigates methods for eliminating heavy metals from car wash wastewater, focusing on adsorption techniques using the flocculation test. Recent advancements highlight the effectiveness and eco-friendly attributes of natural bentonite and modified bentonite. The primary goal is to assess the capacity of these clays in adsorbing heavy metals without the need for additional chemicals. Our findings demonstrate that modified bentonite holds promise in removing copper and zinc from car wash wastewater, achieving reductions of up to 90%, while iron reduction was around 50% with modified bentonite-zeolite. For iron reduction, raw bentonite alone proved effective, achieving 70% to 80% removal without the combination with zeolite. Additionally, we evaluate the treated water’s suitability for recycling and reuse. While iron, copper, zinc, and pH levels meet recommended standards, other factors like turbidity, color, temperature, and total dissolved solids play critical roles in determining water quality for car wash applications. This study shows that turbidity, color, and total dissolved solids significantly increased due to the natural color of bentonite clay, with no chemical additives used to neutralize the color. Despite these increases, all parameters, except for color, fall within the acceptable range as per the National Water Quality Standard and the Recommended Raw Water Quality Standard. To further enhance the effectiveness of bentonite for heavy metal adsorption and gain deeper insights into its adsorption mechanisms, future research should utilize advanced characterization techniques, such as X-ray diffraction and scanning electron microscopy, to better understand the surface properties and structural changes of bentonite before and after modification, as well as following heavy metal adsorption.

Keywords: Bentonite clay; zeolite; car wash wastewater; heavy metals; iron; copper; zinc

Traditional coastal protection strategies frequently depend on man-made structures that may have negative environmental impacts and have limited long-term sustainability. There is a pressing need to develop a new approach to address the issues. This study aims to investigate the stability of seashell blocks when exposed to wave forces, the behaviour of seashells when partially submerged, fully immersed, and exposed, and how seashells react to regular and irregular waves. Multiple experiments with varied wave amplitude and frequency are performed using a wave flume maker to evaluate the attenuation of waves. In this study, seashells were used as models with the application of a flume wavemaker in UiTM Shah Alam’s laboratory. The models reproduce the effects of ocean waves. However, the research is restricted by the flume wavemaker’s dimensions, which are 20 meters in length with the generating equipment and a maximum water depth of 0.4 meters. Parameters including frequency, wavelength, and amplitude were measured using pressure sensors and wave probes. The findings show that the partially submerged seashells performed better in regions with shorter coastal waves. The width of a submerged breakwater’s crest can be cut in half by using seashell blocks. The findings can significantly facilitate the development of long-lasting and efficient coastal protection measures, as well as the design, construction, and monitoring of seashell block structures. Additional research is required to determine the cost, lifespan, and effectiveness of shell blocks in different coastal environments.

Keywords: Wave flume; seashells; regular wave; irregular wave; submerged wave

Malaysia’s water supply has shifted from abundant to scarce, prompting a thorough examination of potential solutions, particularly using Tasik Biru Seri Kundang’s untapped resources. Assessing the reservoir’s capacity to provide clean water consistently amidst increasing demand is crucial. The objective was to analyze Tasik Biru Seri Kundang’s water characteristics to determine its suitability as a drinking water source, which was evaluated through the Water Quality Index (WQI) and heavy metal concentration measurements. The water quality analysis involved field and laboratory testing, assessing parameters such as pH, dissolved oxygen, turbidity, chemical oxygen demand (COD), biochemical oxygen demand (BOD), suspended solids (SS), and ammonia-nitrogen (AN). The findings of the study showed that the pH was 7.26 and 7.67, the dissolved oxygen (DO) was 9.77 and 7.15 mg/L, the chemical oxygen demand (COD) and biochemical oxygen demand (BOD) was 0 mg/L each, the suspended solids (SS) were 10 and 7 mg/L. The ammonia-nitrogen (AN) was 0.08 and 0.1 mg/L, separately. According to the results, all input points were categorized as Class I, indicating that no treatment was required for the water supply. Concentrations of heavy metals, including chromium (Cr), iron (Fe), copper (Cu), zinc (Zn), and manganese (Mn), were measured at levels such as 0.017 and 0.086 mg/L for chromium (Cr), 0.25 and 0.53 mg/L for iron (Fe), 0.21 and 0.26 mg/L for zinc (Zn), 0.09 and 0.08 mg/L for copper (Cu), and 0.021 and 0.044 mg/L for manganese (Mn). While most parameters met WHO standards, chromium levels at the outlet exceeded the permissible limit of 0.05 mg/L, indicating a high concentration of heavy metals. Tasik Biru Seri Kundang exhibits favourable water quality characteristics, primarily meeting drinking water standards. However, elevated chromium levels at the outlet point necessitate corrective measures to ensure compliance with regulatory guidelines and safeguard public health.

Keywords: Ex-mining lake; heavy metals; Water Quality Index (WQI); water quality

Bamboo has been identified as a future material for the primary, secondary, and tertiary sectors of the economy with reference to the Bamboo Industrial Development Action Plan in Malaysia 2021-2030 as bamboo is a natural material with high mechanical qualities and a quick reproduction rate. To support this vision, the construction industry needs structural design values. Currently the structural design values for structural bamboo for Malaysian species are not yet available as most of the R&D is focused on the upstream study and non-structural products. Therefore, this study investigates the physical and mechanical properties of a structural bamboo species namely Buluh semantan (Gigantochloa scortechinii) that is the prominent species being used in structural applications. The preparation of specimens and the physical and mechanical testing; bending, shear and compression in direction parallel to the fiber were conducted in accordance with ISO 22157. The properties obtained were used to derive the characteristic capacity of each property. The determination of allowable stresses is based on the characteristic capacity at 5th percentile in accordance with BS EN14358. These derived outputs provide new design data based on capacity grading for Malaysian bamboo and provide alternative environmental-friendly and sustainable construction materials. The results will be soon incorporated in the ISO Standard. This is aligned with the vision to foster green and sustainability building.

Keywords: Characteristic strength; bamboo culm; natural bamboo

A cement-based composite, ultra-high-performance concrete (UHPC) helps both new and old buildings last longer in service. The growing demand for quality building materials and applications has led to the emergence of various commercial UHPC formulations after decades of research and development. Nevertheless, they are costly and necessitate strict design specifications. Infrastructure like bridges commonly experience structural vibration and static loads during traffic congestion, which can reduce their service life. This study examines the impact of the length and pattern of Glass Fibre Reinforced Polymer (GFRP) sheets wrapped around UHPC beams to strengthen them. The tested UHPC beams had dimensions of 100 × 100 × 500 mm. One beam was tested without GFRP reinforcement, while six beams with various GFRP patterns were subjected to a four-point loading test. The study assessed the initial fracture load, energy absorption, deflection, and ultimate load capacity. Compared to unwrapped beams, the experimental results indicated that GFRP-wrapped beams exhibit substantially higher initial and final load-carrying capacities. The results reveal that GFRP reinforcement can greatly enhance the longevity and structural efficiency of UHPC beams.

Keywords: Ultra-high-performance concrete; fiber-reinforced polymer; glass fiber-reinforced polymer; flexural test

Water quality assessment is crucial for human and environmental health, but studies often face challenges with missing or incomplete data across seasons. This study evaluated the water quality of the Langat River in Selangor, Malaysia, during the wet season, focusing on Water Quality Index (WQI), water classification, and trace metal concentrations. The WQI model, used by Malaysia’s Department of Environment (DOE), serves as a tool for assessing water quality. Water samples were taken from three sites: Kampung Hulu Kuala Pansoon (upstream), Pekan Bt 18 (midstream), and Nanding (downstream). Results showed significant water quality degradation from upstream to downstream, with WQI of 88.01 (Class II) at Kampung Hulu Kuala Pansoon, while both Pekan Bt 18 and Nanding fell into Class III with WQI of 76.50 and 71.68, respectively. While Class II indicates clean water, Class III reflects slightly polluted conditions based on the National Water Quality Standard (NWQS). Population density and land use types were identified as factors in this decline. Trace metal analysis as arsenic, chromium, cadmium, lead, aluminum, zinc, and manganese were present downstream. Although most levels were below NWQS limits, aluminum at 0.071mg/l exceeded permissible values, and manganese 0.09 mg/l detected to be close to the allowable threshold. The small dataset limits accuracy but adds insight to water assessment in wet season. Future studies need more sampling locations and hydrological data. In supporting SDG 6, continuous collaboration with state authorities aims to prevent degradation, ensure Class IIA compliance, and protect water supplies for Selangor’s Water Treatment Plants.

Keywords: Water Quality Index (WQI); Langat River; heavy metals; water classification; wet season

Geopolymer mortar presents a promising alternative to traditional cementitious materials, with the potential to significantly reduce CO2 emissions and support the development of sustainable construction materials. This study investigates the use of waste rubber tyres as a partial sand replacement in rubberised geopolymer mortar, addressing the environmental issue of tyre disposal. Annually, approximately one billion tyres reach the end of their life cycle, with only about 50% being recycled and the rest ending up in landfills. The research evaluates the effects of substituting sand with crumb rubber (CR) at 20%, 40%, 60%, and 80% proportions in geopolymer mortar, focusing on compressive strength, tensile strength, and workability. Results from workability tests revealed that increasing CR content reduced the slump flow by up to 30%. Furthermore, compressive and split tensile strength tests showed a decline in strength with higher CR content. The optimal replacement level of CR was found to be 20%, achieving a compressive strength of 33.35 MPa and a split tensile strength of 3.4 MPa using a GGBS-WCT mix. These findings underscore the potential of utilizing recycled waste materials as aggregate replacements, with significant implications for improving the sustainability and mechanical performance of construction materials.

Keywords: Geopolymer mortar; compressive strength; split tensile strength; crumb rubber

Pavement degradation throughout its design life requires rehabilitation to maintain its functionality. Conventional repair methods, such as ‘remove and replace,’ are costly and environmentally unfriendly. Cold in-place recycling (CIPR) has emerged as an eco-friendly alternative for addressing severe pavement damage. CIPR involves recycling the existing pavement and part of the base layer, which are then compacted to form a new base layer with the addition of a stabilizing agent. In Malaysia, cement is a commonly used stabilizing agent. However, the extensive use of cement raises environmental concerns, as its production contributes between 5-9% of global CO2 emissions. This study explores partially replacing ordinary Portland cement (OPC) with ground coal bottom ash (GCBA) and using calcium chloride (CaCl₂) as an accelerator to address this issue. The study varied OPC content from 1-4%, with GCBA and CaCl₂ ranging from 0-3%. An unconfined compressive strength (UCS) test was conducted to analyze the effects on compressive strength and strength development over time. Results indicated that the optimal GCBA percentage for cement replacement is 1%, while the optimal CaCl₂ content is between 1% and 2%. Overall, compressive strength increased with curing time, highlighting the potential of this innovative approach to pavement rehabilitation.

Keywords: Cold in-place recycling (CIPR); stabilizing agent; ordinary Portland cement (OPC); ground coal bottom ash (GCBA); calcium chloride (CaCl2 ); unconfined compressive strength

The Klang Valley, encompassing Kuala Lumpur and Selangor, faces recurrent flooding due to rapid urbanisation and inadequate drainage systems, particularly during monsoon seasons. This research aims to develop a comprehensive framework for enhancing regional flood disaster management. Data were collected from 255 civil engineering professionals through an online survey, with descriptive statistics used to analyse the challenges, practical solutions, and stakeholder roles in managing floods. Key findings highlight that rapid urbanisation and insufficient drainage infrastructure significantly contribute to flood vulnerability. Respondents rated floods as one of Malaysia’s most common natural disasters, with a mean score of 3.90, while lack of public awareness on flood preparedness scored lower at 3.77. Comprehensive urban planning was identified as the most effective solution (mean score of 3.88), followed by investing in drainage infrastructure (mean of 3.73). The study underscores the need for centralised coordination among stakeholders, receiving strong support with a mean score of 3.87. The proposed framework integrates three key phases: mitigation, focusing on urban planning and infrastructure improvements; preparedness, which involves enhancing public awareness and emergency response systems; and response/recovery, ensuring effective crisis management and long-term rehabilitation. The framework emphasises collaboration between government agencies, local authorities, and communities to enhance flood resilience. This research provides valuable insights for developing sustainable, long-term strategies for flood disaster management in the Klang Valley, addressing the challenges posed by urbanisation, climate change, and infrastructure limitations.

Keywords: Flood; flood disaster management; challenges in flood disaster management