Penandaan jalan pantulan tepat elak nahas

WALAUPUN kemalangan berlaku disebabkan pelbagai faktor pendorong, penggunaan penandaan jalan yang bagus tidak seharusnya dipandang enteng

Evaluation of Malaysian asphaltic concrete mixture using superpave and marshall mix design method

Rapid development of road infrastructure in Malaysia has led to better researched of asphaltic concrete mixtures. Currently, the conventional Marshall method is widely used to design flexible pavement with bituminous surfacing as wearing course in Malaysia. In 1987 to 1993, strategic highway research program (SHRP) developed a new concept for the design of asphaltic mixtures referred to as Superior Performing Asphalt Pavement (Superpave). This evolvement has certainly improved the asphaltic concrete mixtures especially in terms of the compaction mode. In this study, four different types of mix that meet both Superpave and Malaysian gradation limits were developed and designed using both Superpave and Marshall method. Specimens from both types of mix were also prepared at the optimum asphalt contents. The specimens were also subjected to moisture induced damage test and Indirect Tensile Strength test. Volumetric analyses of the mixes showed that the optimum asphalt content and voids in mineral aggregate (VMA) of the Superpave mixtures is lower than Marshall mixtures. An average of 30 and 20 percent increment in tensile strength is evident for Superpave mixtures conducted for 12.5mm and 9.5mm mixtures compared to Marshall designed mix. However, all mixtures are able to resist deterioration due to moistur

The effect of preservation maintenance activities in asphalt concrete pavement sustainability

Pavement infrastructure is crucial to quality lifestyle and affluence of society. Since the pavement structure deteriorates after a while, appropriate pavement preservation maintenance is essential to attain a superior performing, safety, and economic pavement network for the users. Nowadays, within a modern society resources and budget are restricted that make it necessary for transportation agencies to discover approaches to use the resources to optimize benefits included in daily operation. Simultaneously, focus on the idea of environmental sustainability has increased substantially. Pavement preservation assists environmental sustainability by preserving energy, raw materials, and mitigating greenhouse gases (GHG) by maintaining good roads in the perfect condition. Thereby, a sustainable pavement maintenance program should look into allocating budget and resources to pavement preservation. Various types of pavement preservation treatments use different levels of energy and produce GHG emissions. Preservation treatments considered in this study included thin hot-mix asphalt (HMA) overlay, chip seal, slurry seal and crack seal. This research states the methodology in sustainable pavement preservation maintenance. Its focus is on quantifying and recognizing which of these pavement preservations practices minimize environmental impacts. As the economic is one of the components in triple bottom-line in sustainability, the next step is focusing on cost-benefit of preservation maintenance activity and comparing by rehabilitation activity. This research aims to persuade pavement organization to apply correct perseverance activity on the right time and proper manner to enhance sustainable development

Predictability of complex modulus using rheological models

The objective of this study was to investigate the advantages and disadvantages of several linear visco-elastic rheological models applied to the unmodified and polymer-modified bitumens. It was found that all the models studied can be used to predict the linear visco-elastic of unmodified bitumens, aged and unaged samples reasonably well. In contrary, this condition was not really applicable on polymer-modified bitumens particularly for the unaged samples. The measured and predicted data was assessed using the discrepancy ratio (Ri), Mean Normalized Error (MNE) and Average Geometric Deviation (AGD) goodness of fitting statistical analysis. From the study, the modified Sigmoidal and Generalized Logistic Sigmoidal models were observed to be the most outstanding models, followed by the Christensen Anderson and Marasteanu (CAM), Christensen and Anderson (CA) and 2S2P1D (2 springs, 2 parabolic elements and 1 spring) models. The presence of semi-crystalline waves and elastomeric structures in the mixtures render the breakdown of time temperature equivalency principle

Trip Generations at “Polyclinic” Land Use Type in Johor Bahru, Malaysia

Transportation planners need to estimate the trip generations of different land use types in the travel demand forecasting process. The Trip Generation Manual of Malaysia, similar to the Trip Generation Manual of the Institute of Transportation Engineers, USA, provides the trip generation rate at “Polyclinics” as a function of the Gross Floor Area. However, the data for this rate have no line of best fit resulting in the lack of confidence in the prediction. This study considered ten locations in Malaysia and verified the significance of different parameters, i.e. Number of Doctors, Number of Staff, Gross Floor Area and Density of Similar Clinics within 0.5 kilometre radius in Johor Bahru, Malaysia. The study developed regression equations for estimating the peak hours and daily trips at polyclinics in terms of “Number of Doctors”. The developed models can be used in estimating the number of trips generated by the polyclinics in Johor Bahru, Malaysia.</p

Performance of concrete block pavement on sloped road section

The construction of Concrete Block Pavement (CBP) on slopes provides interesting challenges for road engineers. The horizontal (inclined) forces exerted on the road surface are greatly increased due to traffic accelerating (uphill) and braking (downhill). These forces will cause horizontal creep of the blocks down the slope, resulting in opening of joints at the top of the road section. The objective of this study was investigate the effect of parameters include degree of slope, laying pattern, joint width, and thickness of paving block on the performance of CBP on slopes. A laboratory-scale test was used to study these parameters based on steel frame horizontal force and push in tests. Three different laying pattern (stretcher bond, herringbone 90o and herringbone 45o) and joint width (3 mm, 5 mm and 7 mm) were used in the test program. The pavement responses are characterized in terms of horizontal creep and deflection due to applied load for half of an allowable single axle limit. The results indicate that herringbone 45o laying pattern and 3 mm joint width performed best on slopes section. The 100 mm paver thickness is found to be more stable than 60 mm thickness from aspect horizontal force resistant. The results also indicate that the increase of the slope increase the horizontal creep, but decrease of the pavement displacement

Wajibkan pita pemantul cahaya terhadap semua kenderaan berat

Pelanggaran membabitkan kenderaan berat seperti treler dengan kenderaan yang lebih kecil seperti kereta selalunya akan berakhir dengan kecederaan parah atau lebih teruk lagi, menyebabkan kematian terhadap penumpang kenderaan lebih kecil

Evaluating the cooling rate of hot mix asphalt in tropical climate

This paper aims to investigate the environmental effect on cooling rate and to determine the appropriate time available for compaction (TAC) using laboratory tests. This includes the study parameters, namely solar flux, base and ambient temperatures (daytime and night-time paving) and wind velocity, focusing on hot mix asphalt (HMA) asphalt concrete wearing with 14 mm nominal maximum aggregate size (ACW14) mix type for the wearing course and ACB28 mix type for the binder course. Samples were prepared in slab moulds 30.5 cm × 30.5 cm × 5 cm and compacted using a manually operated steel-roller. Readings were taken by averaging the temperature measurements at the middle and surface of the slabs and a temperature of 160 ºC was used as the mixing temperature. A control sample was prepared for each mix type and tested in the laboratory without the influence of wind velocity and solar flux. It was found that the cooling rate of HMA is significantly affected by environmental factors, thus influencing the TAC. The TAC tends to decrease by 15-50% during windy and night conditions but increases by up to 100% during daytime conditions compared to the control samples

Effect of moisture damage on gap-graded asphalt mixture incorporating electric arc furnace steel slag and copper mine tailings

Water damage is a vital factor affecting the durability of gap-graded asphalt. There is an urgent need for a pragmatic and reasonable test to evaluate this parameter. Previous research has proposed that tensile strength ratio is a promising test for this application. Therefore, the aim of this paper is to evaluate the effect of moisture damage on gap-graded asphalt mixture incorporating electric arc furnace (EAF) steel slag and copper mine tailings (CMT). Four material mixtures of eight mix designs were investigated. Each mix was conditioned in water for 24-hour and 48-hour before testing. The study adopted retained strength index (RSI), durability index (DI) and tensile strength ratio (TSR) to describe the durability of gap-graded asphalt incorporating EAF steel slag and copper mine tailings. The results reveal that all the mixes fulfill the prescribed criteria. Also, there is a strong correlation between the retained strength index and the durability index with a strong coefficient of determination, R 2 of 0.9543. The results of the study further showed that gap-graded asphalt mixture incorporating EAF steel slag and copper mine tailings did not seem to pose any problem