Azman Mohamed

Permeability and Strength of Porous Concrete Paving Blocks at Different Sizes Coarse Aggregate

Porous concrete paving block (PCPB) is a block with continuous voids which are intentionally incorporated into concrete. The permeability and strength of PCPB with different sizes of coarse aggregate was presented in this study. Three different sizes of coarse aggregate were used; passing 10 mm retained 5 mm (as Control), passing 8 mm retained 5 mm (CA 5 – 8) and passing 10 mm retained 8 mm (CA 8 – 10). Furthermore, a series of test were conducted in this study such as compressive strength, porosity and permeability. It was found that the size of coarse aggregate affects the strength and porosity of the specimens. It was also shown that PCPB with CA 8 – 10 resulted in low strength, but high in porosity and permeability compared to the other blocks. Beside that PCPB using CA 8 – 10 is able to remove surface runoff efficiently.

Effect of various filler types on the properties of porous asphalt mixture

The open structure of porous asphalt exposes a large surface area to the effects of air and water, which accelerates the oxidation rate and affects the coating properties of the binder. These factors may influence the adhesive strength of the binder-aggregate and lead to cohesive failure within the binder film, contributing to aggregate stripping and moisture damage. The addition of fillers in asphalt mixtures has been identified to stiffen the asphalt binder and improve mixture strength. This study investigates the effect of various filler types (hydrated lime, cement, and diatomite) on the properties of porous asphalt. Compacted samples of porous asphalt were prepared using Superpave gyratory compactor at the target air void content of 21%. Each sample was incorporated with 2% of filler and polymer-modified binder of PG76. The morphology and chemical composition of fillers were investigated with a field emission scanning electron microscope (FESEM) and energy dispersive X-ray (EDX) analysis. The properties of porous asphalt were evaluated in terms of permeability, abrasion loss, resilient modulus, and indirect tensile strength. All mixtures were found to show high permeability rates. Mixtures with hydrated lime exhibited lower abrasion loss compared to mixtures with cement and diatomite. The use of diatomite increases the resistance of the mixtures to rutting and moisture damage compared to other fillers as shown by the enhanced resilient modulus and indirect tensile strength.

Sound Absorption and Morphology Characteristic of Porous Concrete Paving Blocks

In this study, sound absorption and morphology characteristic of Porous Concrete Paving Blocks (PCPB) at different sizes of coarse aggregate were presented. Three different sizes of coarse aggregate were used; passing 10 mm retained 5 mm (as Control), passing 8 mm retained 5 mm (8 – 5) and passing 10 mm retained 8 mm (10 – 8). The sound absorption test was conducted through the impedance tube at different frequency. It was found that the size of coarse aggregate affects the level of absorption of the specimens. It also shows that PCPB 10 – 8 resulted in high sound absorption compared to the other blocks. On the other hand, microstructure morphology of PCPB shows a clearer version of existing microcracks and voids inside the specimens which affecting the results of sound absorption.

Performance of asphaltic concrete incorporating styrene butadiene rubber subjected to varying aging condition

The influence of styrene butadiene rubber (SBR) on asphaltic concrete properties at different aging conditions was presented in this study. These aging conditions were named as un-aged, short-term, and long-term aging. The conventional asphalt binder of penetration grade 60/70 was used in this work. Four different levels of SBR addition were employed (i.e., 0 %, 1 %, 3 %, and 5 % by binder weight). Asphalt concrete mixes were prepared at selected optimum asphalt content (5 %). The performance was evaluated based on Marshall Stability, resilient modulus, and dynamic creep tests. Results indicated the improving stability and permanent deformation characteristics that the mixes modified with SBR polymer have under aging conditions. The result also showed that the stability, resilient modulus, and dynamic creep tests have the highest rates compared to the short-term aging and un-aged samples. Thus, the use of 5 % SBR can produce more durable asphalt concrete mixtures with better serviceability.