One of the causes of premature failure is moisture damage due to loss of adhesion and cohesion which then lead to stripping and decrease in mixture strength. Previous studies have shown that adding additive, such as nano clay, nano carbon and nano calcium, to binder is useful in enhancing mixture properties. In this study, the effect of adding nano-clay on mixture properties was determined. Nano clay in the amount of 2 and 4% by weight of bitumen was added to 60/70 penetration grade bitumen and mixed at a temperature of 150 °C using the melt blending technique at a shear rate of 2000 rpm. The indirect tensile strength (ITS) test was used to evaluate the cracking properties of the asphalt mixtures and the tensile strength ratio (TSR) was calculated to determine the degree of asphalt mixtures’ resistance to moisture damage. The results for the mixtures modified with nano clay were compared with results for mixtures modified by adding 2 and 4 % by weight of bitumen polymer modified bitumen (PG76), hydrated lime and cement. The addition of polymer appears to result in the greatest potential benefit amongst the modified binders and its highest TSR value indicate that polymer modified binder is the least susceptible to moisture damage.Keywords: Nano-clay, polymer, moisture damage, indirect tensile strength

This study was conducted to investigate the hydrodynamic characterisation of channel with submerged vegetation. Aquatic plant provides a variety of ecosystem services and plays an important role in the hydrodynamic behavior, the ecological balance and the characteristics of the river. It has an effect on flow resistance and gives great impact on the water level. Laboratory experiment was conducted to investigate the effect of plant densities to flow profile using wood dowel to represent the real plant which was carried out in a hydraulic flume. Solid volume fraction (SVF) is used as vegetation density in this study whereby SVF 3.14% as high vegetation density and SVF 0.79% as low vegetation density. Experimental studies were conducted in uniform flow condition with Reynolds number 554 for lower vegetation density and Reynolds number 375 for higher vegetation density. Results show that the longitudinal velocity magnitude decreases approximately 30% with vegetation density increases from SVF 0.79% to SVF 3.14%. Average velocity, u for this experiment is equal to 4.44 cm/s for lower vegetation density and 3.00 cm/s for higher vegetation resulting calculated Manning’s roughness equal to 0.0937 for higher vegetation density and 0.0633 for lower vegetation density. Furthermore turbulent kinetic energy (TKE) and turbulent intensities are both greater in higher densities vegetated channel compared to the lower densities. Data analysis also calculated the drag coefficient, CD which is equal to 1.999 for higher vegetation density and 3.680 for lower vegetation density.Keywords : vegetation density, turbulent kinetic energy, turbulence intensities, flow resistance and drag coefficient

This study seeks to identify areas with potential new marine energy in the west coast of Peninsular Malaysia, focusing on the states of Perak and Selangor. The sources of marine energy discussed in this study are from the wave and tidal. The data relating to the new marine energy was collected from the related government departments involved and then was analyzed by using Microsoft Excel software to plot graphs of all the non-spatial data. This study also utilised GIS applications to display the potential for wave energy in the specified area. The spatial analysis showed that the despite high potential of harnessing marine energy in the study area and need the support from the power generating equipment to enhance the energy power. From this study, it is concluded that the potential for renewable marine energy from waves and tidal is at the waters of Permatang Sedepa and Port Klang areas.Keywords: Renewable Energy, Wave Energy, Tidal Energy, Geographic Information Systems (GIS)

Visual observation is the most common method to define the incipient sediment motion to-date. However, the definition can be subjective between researchers, whereby the incipient or threshold criteria of sediment motion depends on the interpretation when the sediment becomes mobile from the state of immobility. This study attempt to investigate the variation of incipient sediment motion value over varying sediment sizes due to subjectivity effect. Three observers with different research background individually determined the critical shear stress, using the same definition of threshold critera. The Shields profile obtained was similar for coarser particles and started to deviate for fine sediment region. This paper found that the existence of variation in the incipient sediment motion, in particular for finer sediment size, with particle Reynolds number Re* < 10.Keywords: Incipient sediment motion; visual observation; Shields Diagram

Roof structure should be properly designed to withstand any applied loads and stress. The distribution of the load on the roof system can be divided into three types which are dead load (roof structure), live load and wind load (stress due to dynamic interference). Wind load is the main stress experienced by the roof. The stability of the roof depends on its support such as roof frame, pillars, walls, beams and foundations. The aim of this study is to determine the maximum pressure distribution on the roof when been subjected to high wind load caused by extreme wind speed through computer simulation. This maximum pressure might cause failure in the roof structure. In this study, a series of parametric studies were carried out which include different type of roof shape, different angle of roof pitch and different angle of wind attack. Through simulation results, it was found that the hip and gable roof type has experienced the biggest failure for wind in direction of 0°. Besides that, it is evident from the results that the hip roof type with an angle of 10° is more practical and has less damage. From these simulation results, the most critical areas with high pressure distribution can be identified.Keywords: Extreme wind; pressure distribution; computer simulation; roof structure; turbulent flow k-z

Statistical analysis and downstream variation in the fluvial sediment mixture were studied along three different rivers in Selangor i.e. Sungai Langat (Sg. Langat), Sungai Selangor (Sg. Selangor) and Sungai Tengi (Sg. Tengi). The aim of this study is to analyse the changes in grain size distribution in the downstream direction in three different classes of rivers, less, medium and fully development along the river banks. Samples were spatially and systematically collected at a distance about 3-5 kilometers between each point. Sediments were dried, sieved and further characterised using the GRADISTAT software. Results showed that the mean size of bed materials in Sg. Selangor and Sg. Langat were decreasing along the downstream towards the estuary. Meanwhile, an opposite trend was obtained for Sg. Tengi where the mean size of the bed material was found increasing towards the downstream of Sg Tengi’s river mouth. Different variation was also observed for sediment parameters of sorting and skewness which reflect decreasing of sediment size follow the downstream of the rivers. Furthermore statistical analysis of kurtosis showed that there were no variation occurs along the three rivers where most of the sediment mixture is a mesokurtic type, normal distribution of bed sediment sizes. Beside that statistical analysis also show from the bivariate plots indicate that the sediments are mostly medium sand, poorly sorted and has profile of either symmetrical or fine skewed.Keywords: grain size distribution; Sungai Langat; Sungai Selangor; Sungai Tengi

This paper is concerned with the ultimate load behaviour of perforated thin-webbed steel plate girders with inclined web stiffeners. Non-linear modelling and analyses were carried out on simply supported plate girders using a commercial finite element software, LUSAS. The girders are of practical size and subjected to a single concentrated load applied at the centre of gravity of the section. Effects of inclination degree of stiffeners and central web openings on the performance and behaviour of such girders are investigated. Variations of ultimate strength, failure characteristic and load-deflection response are obtained from the analyses. The load carrying capacity is found to increase significantly when the inclined intermediate stiffeners were provided to the girders; to the extent of 38% for the unperforated girders whilst 45% for those having web openings. Reduction of shear strength due to presence of web openings may also be improved from 56% in the girders stiffened vertically to only 24% in the girders provided with inclined stiffeners of 30o.Keywords: slender girder; web opening; inclined stiffener; non-linear analysis; ultimate load behaviour

Food premise refers to the cafeteria and restaurants which is a major contributor to water pollution. Contamination occurs due to the discharge of wastewater containing substances such as fats, oils and grease from the sink of the food premises into the drainage and irrigation system without passing through any separation process. The objectives of this study are to determine the level of waste cooking oil management in the cafeteria through the monitoring and data collection of waste cooking oil collection from the cafeterias; and to determine the level of water pollution as an indicator of pollution due to the cafeteria’s activities. The methods of collecting the weight of waste cooking oil produced from 18 cafeterias was recorded and analysed to obtain the total amount and average of weight for waste cooking oil collected. The result shown that there was an increment of used cooking oil collection as well as the active participation of the six cafeterias with a total accumulation of 1350 kg/year was successfully collected. This indicates to certain degree the effectiveness of the proposed collection system for the used cooking oil. The results of oil and grease contents for four sampling location were moderately high between 8.8 mg/L and 25.5 mg/L and this is an indicator to oil and grease pollution problems due to cooking activities and require a solution of oil and grease traps installed at each cafeteria.Keywords: used cooking oil; fats and grease; cafeteria; oil and grease traps

Temporal analysis is used to obtain changes in water quality along the Straits of Johor. Boxplot is used to show graphically on the temporal pattern of yearly and monthly temperature, conductivity, pH, dissolved oxygen (DO), total suspended solids (TSS) and oil and grease in the water from 2003 to 2013. The ANOVA test is carried out to determine the significance of the mean of each parameter between years. The boxplot shows a particular trend for each of the marine parameters over the year and the seasonal pattern is only apparent in temperature. The ANOVA test indicates a significant difference in the means of each water quality marine parameter across the year. The changes in each of the marine parameters over the year could be associated to the natural features of the marine water and climate change. The seasonal pattern however is only apparent in temperature which could be influenced by the monsoon seasons.Keywords: Temporal Analysis, Straits of Johor, Water Quality, ANOVA

Concrete is a composite material that is important and is often used in construction because concrete has a high compressive strength. Aggregates consisting of 70% by volume of concrete, thus the aggregate properties is believed to affect the behavior of concrete during concrete structures subjected to dynamic loads strongly (e.g. gas explosions or weapons, falling rocks and earthquakes). The behavior of concrete under dynamic loads can be found by identifying the dynamic increase factor (DIF). When concrete under static and low-rate loading, concrete material damage is governed by the relatively weaker strength of mortar and the interface transition zone (ITZ), but if the concrete under high-speed loading, cracking propagate through aggregates, therefore results in increase the strength of concrete. This research aims to study the effects of normal aggregates on the dynamic behavior of concrete by using the finite element method using LS- DYNA software. Models of concrete with different types of aggregates such as granite, basalt, limestone, and sandstone are used in this study. Numerical simulation of model concrete under compressive stress at different strain rate is carried out. At low strain rate loading, concrete failure only occurred in the mortar and not too obvious. While, at high strain rate loading, failure occurred in the aggregate and failure in the mortar is apparent. Basalt that is high strength has high DIF value and limestone has the lowest value of DIF.Keywords: aggregate; dynamic increase factor; strain rate

The aim of this study was to determine the appropriateness of using coconut shells to replace the coarse aggregate size of 10 mm. This study was conducted with a sample of control and also samples of the mixture in the percentage of 10, 20, 30, and 40% of the weight of aggregate following PWD Specification. Various experiments were conducted to test the robustness and suitability of coconut shells to replace aggregates in flexible pavement. The tests performed follow Superpave mix design tests, and for the performance test, indirect tensile modulus, dynamic creep and static creep were conducted. Based on the test conducted, the coconut shells found can serve as substitution for aggregate at less than 10% of the aggregate total weight for the size 10 mm. The use of coconut shell in this study was to save the costs, as the cost of aggregate now rising and coconut shell material is easily available.Keyword: coconut shell; creep; resilient modulus; asphalt mixture