Addressing GHG emissions from land transport in a developing country

The number of motor vehicles in Malaysia is growing at a significant rate, from around 15 million in 2005 to around 25 million in 2014. Based on the National GHG Inventory as reported to UNFCC, as a whole the transport sector has consistently remained the second largest GHG emitting sector in the country, accounting for 20% of the country’s total GHG emissions in 2014 of which about 18% comes from road transportation. In this paper, a possible approach in addressing the GHG emissions from the land transport sector is presented. The avoid-shiftimprove strategy is employed to determine the possible measures to deal with mitigating the GHG emissions. Computation of GHG emissions for 2014 revealed that car is the vehicle with the biggest contribution, due to its large numbers and also VKT. Motorcycles, on the other hand, have relatively lower GHG contribution despite its huge numbers, while goods vehicle have significant GHG contribution despite its small number of vehicles. Public transport (both rail and bus) can significantly reduce GHG emission for each passenger-kilometer compared to other alternatives. Opting for smaller vehicle can also reduce GHG emissions. Another potential solution towards lower GHG emission is adoption of electric mobility and alternative fuel

The effect of coarse to fine aggregate ratio on the fresh and hardened properties of roller-compacted concrete pavement

Roller-compacted concrete pavement (RCCP) is an economic and durable rigid pavement. Although about half century has passed since the first RCCP was implemented, information about this type of concrete is still limited. RCCP as a zero-slump concrete, has lower cement content than conventional vibrated concrete. Therefore, the quality of the aggregates has a significant impact on the properties of concrete. For this reason, the quantity of coarse and fine aggregates in RCCP should be optimized. This study investigates the effect of coarse to fine aggregate (C/F) ratio on the fresh and hardened properties of two RCCPs with cement contents of 9% (204 kg/m(3)) and 12% (268 kg/m(3)). Compressive strength, splitting tensile strength, flexural tensile strength, Vebe time and porosity tests were carried out. The test results demonstrate that increasing the C/F ratio from 0.6 to 1.8 increased the Vebe time threefold, while increasing the cement content from 9% to 12% decreased the Vebe time by 12%. In addition, increasing the C/F ratio from 0.6 to 1.2 significantly decreased the porosity of RCCP, to about 60% for RCCP with 9% cement and 38% for RCCP with 12% cement. Generally, the most suitable C/F ratio for RCCP appeared to be from 1.2 to 1.4. Thus, to attain a workable, high-strength and durable RCCP, a mix with 12% cement and 1.2C/F ratio is recommended. (C) 2018 Elsevier Ltd. All rights reserved

Mechanical Properties of Cement-Bitumen Composites for Semi-Flexible Pavement Surfacing

Semi-flexible pavement surfacing is a composite pavement that utilizes the porous pavement structure of the flexible bituminous pavement, which is grouted with an appropriate cementitious material. The main objective of this study is to investigate the mechanical properties of cement-bitumen composites as an alternative semi-flexible pavement surfacing material. This involves the selection of acceptable proportions of cementitious grouts as well as the development of cement-bitumen composites. The findings showed that by replacing 5% of the cement with silica fume (with adequate amount of superplasticizer) there is improvement in compressive strength and tensile stiffness modulus. In addition, resistance to abrasion is improved