B.H. Abu Bakar

Bio: B.H. Abu Bakar is an academic researcher from Universiti Sains Malaysia. The author has contributed to research in topics: Crumb rubber & Compressive strength. The author has an hindex of 11, co-authored 27 publications receiving 434 citations. Previous affiliations of B.H. Abu Bakar include University of Anbar.

Characterization of the interfacial bond between old concrete substrate and ultra high performance fiber concrete repair composite

Abstract: The interfacial bond characteristics between normal concrete substrate as old concrete and ultra high performance fiber concrete as repair material have been investigated. Normal concrete substrates were first subjected to different surface preparation methods prior to bonding the ultra high performance fiber concrete to form repair composites. The interfacial mechanical bond of the composites was assessed using slant shear and tensile splitting strength tests. In addition, rapid chloride permeability test was performed to ascertain the potential chloride resistance of the composites. The microstructure of the transition zone between the normal concrete and ultra high performance fiber concrete was also studied using scanning electron microscope. The results generally indicate that surface preparation of the substrate is very much required to obtain superior mechanical bond of the composites; whereby the composites with the sand-blasted substrate providing the most superior mechanical bond. The excellent bond of the composite is also evident through the rapid chloride permeability test, as well as confirms by the scanning electron microscope image of the interface. Hence, the ultra high performance fiber concrete exhibits significant potential as an excellent material for repair and rehabilitation of concrete structures.

Effect of rice husk ash fineness on the chemical and physical properties of concrete

Abstract: The influence of grinding on the physical properties of rice husk ash (RHA) and Portland cement is examined. The optimum rice husk ash grinding time (i.e. to produce a highly reactive product with minimum grinding energy) was determined. Eight different fineness grades of rice husk ash were examined and it was found that rice husk ash ground for the optimum grinding time had a median particle size of 9·52 μm. A rice husk ash dosage of 15% by weight of binder was used throughout the experiments. It was found that the specific gravity and the fineness of the rice husk ash increase with an increase in grinding time. However, the morphology of the rice husk ash changed with grinding. There appears to be an optimum grinding time of approximately 90 min, during which time the compressive strength and strength activity index increase significantly. The use of rice husk ash ground for 90 min (to 9·52 μm particle size) produced concrete with good strength and low porosity.

The Role of Silica Fume in the Adhesion of Concrete Restoration Systems

Abstract: The weak interfacial transition zone between new and old concrete is always paid much attention and controls many properties of repaired concrete, The present work reports a study on the influence of the silica fume on the adhesion of reactive powder concrete (RPC), as a concrete restoration material, with the ordinary concrete (OC) substrate. The results showed that, the silica fume presence in the interfacial transition zone significantly enhances the adhesion strength between RPC and OC substrate. Furthermore, the silica fume particles consume calcium hydroxide, which is in attendance in the interfacial transition zone, and make the zone more dense, uniform and tough.