Investigation on material physical properties for application in seawater-RHA concrete added with coal bottom ash

Abstract

This paper presented the result of a laboratory investigation to determine the properties of the material used for seawater-RHA concrete added with coal bottom ash. Seawater, rice husk ash and coal bottom ash were introduced as eco-material in concrete to totally or partially replace conventional material as an effort to introduce environmental-friendly material. Testing was carried out on sieve analysis, fineness modulus, specific gravity and water absorption which complies with the standard available. In addition, a scanning electron microscope and X-ray fluorescence were conducted on ordinary Portland cement, rice husk ash, coal bottom ash and sand to study the microstructural and element composition of the material. It was found that specific gravity for seawater is slightly higher than tap water. Meanwhile, rice husk ash and coal bottom ash have a specific gravity lower than conventional materials. From the XRF test, rice husk ash is classified as type F pozzolans with silica oxide more than 90 percent and coal bottom ash has more voids compared to normal sand. These investigations are important to ensure good concrete performance especially in controlling water-cementitious ratio, strength and quality of the concrete.