The influence of partially replacing pit sand with quarry dust on the compressive strength of sandcrete blocks

Sandcrete blocks are widely used for wall construction in developing countries, particularly in Africa. The composition of these blocks varies due to the diverse range of materials used. This study investigates the effects of partially replacing pit sand with quarry dust on the compressive strength of sandcrete blocks. Physical parameters of quarry dust and pit sand were determined in accordance with BS 1377-9 (1990), and sandcrete blocks were produced with 20%, 30%, 40%, 50%, 60%, 70%, and 80% quarry dust replacement of sand. After 28 days of curing, compressive strength tests were conducted on the blocks. The results show that a 20% substitution of pit sand with quarry dust produced the highest average compressive strength of 1.46 N/mm². However, the compressive strength of the blocks reduces as the proportion of quarry dust increases. It is recommended that at most 30% of quarry, dust replacements be used for non-load-bearing walls.