Plastic wastes are a major hazard for the environment and their use in the construction industry is increasing day by day. The major drawback of the use of plastic in concrete is an exceptional reduction in strength and workability. This research work explores the effect of sand coating on two types of recycled plastic aggregates, high-density polyethylene (HDPE) and electronic-wastes (E-wastes), as partial replacement of natural aggregates. The replacement ranged from 0% to 30% along with the use of super plasticizer SP-675 and wet lock sealant. Both recycled plastic aggregates are crushed, melted, and ground to convert them into aggregates of 20 mm size. The workability of concrete containing uncoated recycled plastic aggregates (HDPE and electronic wastes), SP-675, and wet lock sealant has been found to be higher than controlled concrete samples with 0% recycled aggregates. Compressive strength, split tensile strength, and flexural strength of such type of concrete is lower than the controlled concrete samples due to the weak bond between the plastic aggregates and Ordinary Portland Cement. After applying the sand coating to improve bonding, the workability is reduced compared to uncoated samples whereas the compressive strength, split tensile strength and flexural strength of the sand coated plastic aggregate concrete is higher than uncoated plastic aggregate concrete. There is a significant increase in workability of concrete after the addition of SP-675 when added as 2% by weight of cement. The wet lock sealant positively affects the strength properties of concrete. It is recommended that the durability of concrete containing uncoated and sand coated recycled plastic aggregates be further explored in future studies.

Despite presenting a very high global warming toll, Portland cement concrete is the most widely used construction material in the world. The eco-efficiency, economy, and the overall mechanical and durability performances of concrete can be improved by incorporating supplementary cementitious materials (SCMs) as partial substitutions to ordinary Portland cement (OPC). Naturally found bentonite possesses pozzolanic properties and has very low carbon footprint compared to OPC. By applying activation techniques, the reactivity of bentonite can be improved, and its incorporation levels can be maximized. In this study, the influence of mechanical and thermo-mechanical activation of bentonite is investigated on properties of concrete. Bentonite was used for 0%, 10%, 15%, 20%, 25%, 30%, and 35% mass replacements of OPC. Mechanical (compressive strength and split tensile strength) and durability (water absorption, sorptivity coefficient, and acid attack resistance) properties were studied. Results of experimental testing revealed that, concrete containing bentonite showed good mechanical performance, while durability was significantly improved relative to control mix. Application of thermo-mechanical activation can enhance the incorporation levels of bentonite in concrete. At 15% and 25%, bentonite produced optimum results for mechanical and thermo-mechanical activation, respectively. Bentonite inclusion is more beneficial to the durability than the mechanical strength of concrete.

The paper focuses on the improvement of the clayey soil (A-6) with the locally available and cheap modifiers, in terms of stiffness behavior of the weak subgrade soil for flexible pavement. The modifiers used include lime (hydrated), marble waste and sand. The soil specimens underwent triaxial testing and Clegg impact testing. Triaxial testing involved the assessment of the resilient modulus (M_R) and impact testing using the Clegg Impact Hammer. According to the study, lime proved to be the most influencing modifier as it improves the stiffness of the weak soil better than other modifiers. A quite accurate statistical relationship between the M_R and the variables (including Clegg Impact) involved in the testing procedure has been established

The energy consumption due to urbanization and man-made activities has resulted in production of waste, heat, and pollution in the urban environment. These have further resulted in undesirable environmental issues such as the production of excessive Anthropogenic Heat Emissions (AHE), thus leading to an increased Urban Heat Island (UHI) effect. The aim of this study was to estimate the total AHE based on the contribution of three major sources of waste heat generation in an urban environment, i.e., buildings, vehicular traffic, and human metabolism. Furthermore, a comparison of dominating anthropogenic heat factor of Darwin with that of other major international cities was carried out. Field measurements of microclimate (temperatures, humidity, solar radiation, and other factors of climate measures) were conducted along Smith Street, Darwin City. Then, surveys were conducted to collect information regarding the buildings, vehicle traffic and Human population (metabolism) in the study area. Each individual component of AHE was calculated based on a conceptual framework of the anthropogenic heat model developed within this study. The results showed that AHE from buildings is the most dominant factor influencing the total AHE in Darwin, contributing to about 87% to 95% of total AHE. This is followed by vehicular traffic (4–13%) and lastly, human metabolism (0.1–0.8%). The study also shows that Darwin gains an average of 990 Wm⁻² solar power on a peak day. This study proves that building anthropogenic heat is the major dominating factor influencing the UHI in tropical urban climates.

This paper investigates the properties of waste plastic film and carbon nanotubes modified asphalt mixes. The composed asphalt mixes have been evaluated for fatigue cracking and rutting. In this research, a total of 30 numbers of samples were prepare...