The reason for failure in engineering component can be attributed to design deficiencies, poor selection of materials, manufacturing defects, exceeding design limits and overloading, and inadequate maintenance. The behaviour of material depends on the chemical, physical, mineralogical, microstructure characteristics and the interaction between them in the concrete. The aim of this research is to investigate some of the properties on the concrete that is containing the lightweight expanded clay aggregates (LECA). Study the microstructure of concrete be able to understand the relationship between structure and behaviour of concrete. Interaction inside the phase of concrete such as dislocations, grain boundaries, phase interfaces, pores and crack can be identified by a microstructure of concrete. Therefore, a microstructure of concrete has been studied under a digital microscope. The properties of LECA were investigated in order to relate the behaviour of aggregate in the concrete. LECA were used in the production of lightweight aggregate concrete (LWAC) with the size 50 mm × 50 mm × 50 mm. The results show that LECA has several improvements when compared with normal crushed aggregate. The density of LECA was 520 kg/m3 and its characteristics were round, rough and porous. Besides that, the LWAC shows an excellent strength development, 29.41 MPa compared than normal weight concrete (NWC), 25.57 MPa. The surface of LWAC was darker than NWC due to LWAC experience more hydration of ferrite compound. In addition, the microstructure investigation of the LWAC shows a good bonding between aggregate and mortar at the interface transition zone (ITZ).

 

Keywords:  Lightweight expanded clay aggregates; Digital microscope; Interface Transition Zone

Swale drainage is a broad and shallow drainage that is able to filter runoff before flowing to the main drain and river. This study is focused on the effectiveness of the swale drainage compared to concrete drainage, in terms of pollutant removal and its relationship with the infiltration rate. The chosen site is at Astaka field, in Selangor.
The water quality of the outflow was tested to determine the water quality classes when compared to the Interim National Water Quality Standards (INWQS) for Malaysia. Chemical oxygen demand (COD), total suspended solid (TSS), ammonia nitrogen, pH and turbidity are the five parameters that were tested in the water quality test. The study of infiltration rate of swale outflow was done by using the Mini Disk Infiltrometer and was compared with that of the field without swale. Swale proved to be effective to remove about 40%-60% TSS, 10-70% COD and 30-80% ammonia nitrogen compared to the regular concrete drain. The water turbidity of the outlet is higher than that of the inlet for both types of drainage. Results show that swale has negligible effects towards the pH value. The pH value obtained shows signs of alkalinity of the water outflow. The water quality of the outflow at swale outlet achieved Class II according to the INWQS for Malaysia. Swale at Astaka field had a rate of infiltration of 1.8-2 cm/hour which indicates a smaller rate than the field without swale.

Keywords: Swale; Water runoff; Pollutant removal; Infiltration rate

A pedestrian crossing is a facility designated for pedestrians to cross a road in groups, so that they can be seen by the motorists. Pedestrian crossing is also used by them to cross safely across a flow of vehicular traffic. However, accidents still occur among pedestrians even though there are provisions for pedestrian crossing facilities. The purpose of this research is to identify the level of motorists’ compliance towards pedestrian crossing at Universiti Kebangsaan Malaysia (UKM) which is located in Bangi, Selangor. This research involved 326 respondents among motorists and pedestrian that comprised of UKM’s undergraduate and postgraduate students. This research aims to measure and analyse the level of compliance and the importance of motorists, pedestrian, facilities and maintenance factors using the Importance Performance Analysis (IPA) method. The data were analysed by using the Statistical Package for Science Social (SPSS) 22. The results of IPA were divided into four quadrants where some of the factors must be improved by UKM’s authority and some must be maintained. From the IPA analysis, it was concluded that the street lightings must be improved and upgraded by UKM’s management as the attribute lies on Quadrant 2 where Quadrant 2 represents the attributes that need to be prioritised, so that accidents between motorists and pedestrians can be avoided.

Keywords : Pedestrian crossing; Motorist; Universiti Kebangsaan Malaysia; Importance Performance Analysis

Road maintenance works performed by contractors require validation upon completion. Conventional methods are typically chosen to validate the works. Geographic Information System (GIS) is applied in this study to produce accurate data such that waste from road maintenance costs can be minimised. In this study, Unmanned
Aerial Vehicle (UAV) was used to observe the images of two roads, namely Jalan Gelanggang and Jalan Temuan, both of which are under maintenance at the Universiti Kebangsaan Malaysia. The objectives of this study are; to determine the ability of UAV technology in supervision and verification of maintenance works, and the effectiveness of spatial works in road maintenance. This study then proceeds with analysing data by using ArcGIS and AutoCAD software to determine the width, perimeter, and area of the road that has been maintained. Comparisons were made between these two data which are the data that has been claimed and provided by the contractors (as-built data) and images data of the UAV whenever to get the percentage of the difference for several features of the road. Results from this study showed that the value for width, perimeter, and area of the as-built data for both roads are greater than the value of the image where the UAV data show percentage differences of shape area for Jalan Gelanggang is 3.27% and for perimeter is 1.35%. While percentage differences of shape area are for Jalan Temuan is 4.83% and for perimeter is 2.44%. Therefore, if UAV is used for work validation, the total saving on road maintenance work costs are saved at least RM 6,386.28 for Jalan Gelanggang and RM 5,775.24 for Jalan Temuan.

Keywords: Road maintenance works; Validation; Geospatial; Unmanned Aerial Vehicle (UAV)

Knowledge in modelling unsaturated slope behaviour remains limited. Research findings have challenged the common assumption of fully saturated conditions for all soil problems thus widening the perspective of partially saturated states. The calibration of unsaturated soil parameters requires good understanding of the soil-water
characteristic curve (SWCC) and the permeability functions. The modelling of unsaturated slope behaviour involves the setting out of the model geometry, boundary conditions and flux boundaries when it comes to rainfall. It is a norm where certain unobtainable data had to be assumed and the results are consequently under or overestimated. Hence, this paper aims to validate the numerical techniques in modelling the groundwater flow and safety analyses for a slope model under the effect of typical rainfall in Hubei, China. The model is developed using Finite Element package; Plaxis and the results are compared to the field results and literature findings. The
important parameters of hydrological and mechanical properties were gathered from the literature along with the boundary conditions. The flux boundaries are presented by simulated rainfall for a period of one month and the calculation is conducted in transient flow analysis. The results in terms of pore-water pressure are well
validated with minor differences which can be explained by the unavailability of data for example the void ratio used and exact location of measurement taken in the field and literature findings. The analysis is also extended to calculate the factor of safety which contributes to familiarising the techniques in modelling by means of utilising
the phi-c reduction method. In summary, the results demonstrated that the numerical modelling of unsaturated slope behaviour can be undertaken provided that all major information such as soil parameters, slope geometry and boundary conditions used are available and reliable.

Keywords: Unsaturated slope; Groundwater flow; Factor of safety; Plaxis.

Capacitive proximity sensor is often used in various industrial applications for contactless measurement of an object or target displacement and position. In this research, the capacitive proximity sensor is used for new alternatives in detecting recyclable materials specifically plastic and paper for aiding in the separation process. The detection of the sensor for this study is based on the permittivity values of each material where the sensor is adjusted according to the tested material permittivity. Several experiments have been conducted using different types of papers, plastics, and a combination of both materials for this study. At the end of the experiment, the sensor is able to detect a different type of paper and plastic. The sensor also able to detect the combination of both paper and plastic based on their difference in permittivity values. However, there are some limitations to this system such as the size, density, permittivity values, as well as the distance between both sensor and target are affecting the accuracy of the detection system causing the sensor to fail in identifying the samples.

Keywords: Capacitive proximity sensor; Permittivity; Detection; Recyclable

Traffic impact assessment (TIA) on a proposed commercial development in the neighbourhoods of Ampang Town in Selangor was conducted. In this study, trip rate analysis and regression analysis were carried out to assess future traffic expected to be generated by the proposed new commercial development. Calculations of trips were based on the Malaysian Highway Planning Unit (HPU) Trip Generation Manual (TGM) Malaysia 2010 related to a category of proposed new commercial development. Before and after construction study on the proposed new commercial development at neighbouring critical intersections and roads was carried out to determine existing and projected traffic volumes. A Statistical Package for the Social Sciences (SPSS) software was used to analyse traffic growth rate. This procedure uses a growth factor in the traffic data to show an increase in demand for transport journeys in the future. Then, intersections and roads traffic performances were analysed using the Signalised and Un-signalised Intersection Design and Research Aid (SIDRA) software. Result of SIDRA analysis with traffic projection horizon of year 2026 shows deterioration in Level of Service (LOS) D at one of the existing main junctions leading to the proposed new commercial development. Finally, traffic improvements were proposed to address future impact of generated traffic caused by the proposed new commercial development. Consequently, this study has provided a framework for TIA preparation and would assist developers and local authorities in their decision making to meet all the requirements needed in the design and improvement of traffic flow.

Keywords: Traffic impact assessment; Regression analysis; Trip rates; Level of service

The aim of this research is to determine the performance of effective microorganisms (EM) in the composting of mixed food and yard wastes on an industrial scale. Composting parameters such as temperature, moisture content, pH, and the carbon to nitrogen ratio (C:N), as well as the maturity of nitrogen, phosphorus and potassium (NPK), were determined. For this purpose, the type of EM used to accelerate the composting process is Indigenous Microorganism (IMO). The study, which was conducted using the best EM, accelerated the composting process, wherein it only takes approximately 13 weeks for the decomposition process to occur in each heap. The results show that the final temperature for each heap is between 25.57 and 28.03 ͦ C, the percentage of moisture content is between 45.55 and 60.49%, the pH is between 6.81 and 7:41, the ratio of carbon to nitrogen is between 17:1 and 23:1, the NPK value for nitrogen ammonia is between 0 mg/L and 0.56 mg/L, the potassium content is between 2.25 and 3.25 ppm, and the value of phosphorus is between 0.56 and 0.76 ppm. Based on these results, it can be concluded that the quality of the compost produced for all piles is high. Due to the slight differences in parameters between all piles, the effectiveness of EM IMO was not conclusive for either open or closed aerated piles, and further research needs to be done.

Keywords: Effective Microorganism (EM); Indigenous Microorganism (IMO); Composting; Yard Waste; Food Waste

This paper focuses on the ultimate load behaviour of steel-concrete composite plate girders with inclined stiffeners. For this research, non-linear modelling and analyses were carried out on ten simply supported composite plate girders using a commercial finite element software, LUSAS. The girders are of practical design size and subjected to a single concentrated load applied at the centre of the girder span. Effects of different inclination angles of intermediate stiffeners and web-depth to thickness (d/t) ratios on the post-buckling behaviour of the girders are investigated. Five different angles of stiffeners, measured from the bottom flange, were considered in the research, viz., 90°, 75°, 60°, 45° and 30° while the web thickness, tw used in this study are 2 mm and 3 mm. With the effects of such inclinations, the variations of ultimate load, load-deflection response and failure characteristics were obtained. The load carrying capacity was found to rise significantly of about 32%, as the angle of inclination reduced from 90° to 30°. The ultimate strength of the composite girder also shows a maximum increase of 28%, when the web thickness, tw rises from 2 mm to 3 mm.

Keywords: Composite girder; inclined stiffener; non-linear modelling; ultimate load behaviour; post-buckling

Natural fibre reinforced concrete (NFRC) has been a subject of interest for research in the past few decades due to the many advantages of natural fibres such as abundantly available, lightweight, cheap, diverse and as reinforcement in composite, provide great energy absorption and good impact resistance to the composite. The purpose of this paper is to study the engineering properties (workability, compressive, flexural and split tensile strengths, and impact resistance of NFRC, particularly kenaf (K) and rice straw (RS) fibres. Both fibres are investigated to determine feasibility of using abundant waste (RS) instead of kenaf (planted) as natural fibre reinforcement in concrete for impact resistance application such as roof tiles. Samples consist of untreated kenaf and rice straw fibres, with different percentages by volume of cement (0, 1, 1.5, 2, 3, 4 and 5%), as concrete reinforcement. The slump, compressive, flexural, split tensile strengths, and impact resistance are determined in accordance to BS, ASTM and ACI codes of practice. Results show that, due to high rate of water absorption of rice straw fibre, reduction in workability and compressive strength of RSFRC can be observed compared to KFRC. Increasing the volume of RS fibre leads to high volumes of entrapped air after curing process, resulting in decrease of concrete strength. However, addition of both fibres as reinforcement, enhanced the flexural, split tensile and impact resistance of concrete at up to a certain volume fraction of fibres. The energy absorption of RAFRC at 2% is superior compared to other fibres, except only coir and exhibit better performance in resisting impact even though kenaf has superior properties compared to RA due to its higher ductility compared to kenaf.

Keywords: Natural fibre reinforced concrete; Kenaf; Rice straw; Mechanical properties; Impact resistance

The government of Malaysia has implemented various measures to reduce disposal of daily solid waste to landfills including recycling. Based on the issue, the Universiti Kebangsaan Malaysia took the initiative to organise “Program Masjid Lestari” targeting to enhance recycling practices among the community. The objectives of this study are to identify factors that influence the behaviour of recycling practices in the community and to assess the effectiveness of the awareness programme, “Program Masjid Lestari”. “Program Masjid Lestari” focused on recycling practices among Bandar Baru Bangi and Semenyih residents took place in 2015, 2016 and 2017. The study applies survey instrument and also weight of recyclable items collected during the program. The questionnaires were distributed to the residents who had attended the event at Section 3 and Section 4, Bandar Baru Bangi and also Bandar Rinching, Semenyih. The survey data was analysed using Statistical Packages for Social Sciences (SPSS) version 23. Based on the findings, the total recyclable items collected during the program were 800 kg in 2016 and 878 kg in 2017 for Bandar Rinching, Semenyih. Most of the respondents have good knowledge, awareness and attitude towards recycling. However, the involvement of community in recycling practices is still low due to lack of facilities, time and cost constraints. In general, awareness campaigns are able to increase community involvement to recycle. A good advertising and promotion, appropriate time, location and improvement of facilities are the important factors to ensure a successful awareness program that could make an impact on the recycling practice.

Keywords: Recycle; Community; Awareness Program; Behaviour

Shields diagram is used as the main source to determine the incipient motion of sediment. However, incipient sediment motion in the Shields diagram was developed based on non-cohesive sediment where the parameter influencing the motion of cohesive and non-cohesive sediments are different. Therefore, this study attempts to investigate the incipient sediment motion for biological extracellular polymeric substance (EPS) influenced by a cohesive sediment mixture. Percentage of silt with a median grain size of 28μm (which acts as the cohesive material) and fine sand with of 150μm were varied as 10:90, 20:80, 40:60, and 50:50, which formed the cohesive sediment mixture. Two different concentrations of EPS 0.02% (which denotes as low concentration) and 0.1% (as high concentration) were well mixed with the sediment mixture. This study utilised Xanthan gum, which acts as a substitution for EPS. The experiments were conducted in a laboratory flume and the threshold criterion for sediment motion was obtained through observation. The critical Shields parameter θ_c was calculated using the critical shear velocity and root-mean-square horizontal velocity (representing turbulent fluctuations) when few of the particles on the bed was observed to move. Obvious finding from this study is the presence of EPS clearly influence the threshold criteria based on the higher value obtained at sediment mixture with 0.1% compared to the values found for the 0.02% EPS sediment mixture. The values of the critical Shields parameter were monotonously increased as the percentage of silt in the sediment mixture increases. The presence of silt in the sediment mixture increases the sediment stability signifying more hydrodynamic forces are required for the particles to be entrained. The critical Shields parameter obtained based on the critical shear velocity and turbulent fluctuations posed similar trend as described in the well-established Shields curve indicating that the velocity scale used to describe the incipient sediment motion is not a decisive factor.

Keywords: Incipient sediment motion; Silt-sand-EPS mixture; Biological cohesive sediment