Bottom ash as replacement of sand for manufacturing masonry blocks

Abstract

Bottom ash is a waste material from coal combustion and has no specific utilization in Sri Lanka. Usually, they are disposed into environment as a waste material. Bottom ash is a light-weight material, which consists of considerable amount of SiO2. Objective of this study is to utilize bottom ash as replacement of sand for manufacturing masonry blocks. Properties of bottom ash and the structural properties of masonry blocks manufactured with bottom ash were investigated. Solid masonry blocks having the size 360 mm x100 mm x 170 mm were cast with a mix proportion of 1:6 Cement: Sand. Bottom ash, as replacement for fine aggregates, was used in varying percentages: 0%, 10%, 20% and 30%. Compressive strength was determined by crushing the masonry blocks at the ages of 7, 14 and 28 days. In addition, water absorption properties and material cost of the blocks were investigated. It was found that utilization of 20 % of bottom ash for replacement of sand provides greater compressive strength. Structural properties and cost of the bottom ash based blocks are discussed in this paper.