Development of Foam Concrete Blocks with Bottom Ash

Bottom ash, which is a byproduct of coal fired thermal power plants has given rise to major environmental impacts due to its potential hazardous effects. Through this research, attempts were made to use bottom ash as a substitute for river sand in producing foam concrete blocks. This will further contribute to the reduction of excessive river sand mining. In this research main focus was given to develop lightweight concrete blocks incorporating bottom ash and foaming agent. Experimental investigations were carried out by varying bottom ash to cement ratio, water to cement ratio and particle sizes of bottom ash in order to identify the potential of applicability of bottom ash in producing foam concrete blocks. Furthermore, in this study, wet method was used to generate foam by using industrial foam generating machine. By evaluating a range of properties such as compressive strength, drying shrinkage, wetting expansion and water absorption, it was found that the optimum bottom ash to cement ratio for foam concrete is 0.75 which resulted in compressive strength of 3.8 MPa with dry density in the range of 700-850 kgm^-3 which satisfies the requirements of lightweight category masonry blocks.