Assessing the impact of fly ash which is used to replace cement on the technical properties of unburnt concrete bricks

This study is to evaluate the potential of using fly ash produced from thermal power plants to manufacture unburnt concrete bricks. The impact of fly ash which is used to replace cement on the technical properties of unburnt concrete bricks is assessed through experiments of evaluation of slump, volume weight, compressive strength, water absorbing, and drying shrinkage. The fly ash is partially replaced cement from 0 to 50% with the replacement step increases by 10%. The results show that the slump and the water absorbing level of the concrete mixture increase correspondingly to the increase in the content of fly ash in the concrete mixture. However, the compressive strength of the concrete mixture decreases when the content of fly ash increases. The use of fly ash reduces the volume weight and the drying shrinkage of unburnt concrete bricks. This study finds out that fly ash can replace cement up to 40% in unburnt concrete bricks with the compressive strength values at 28 days of age > 7,5 Mpa and up to 50% > 7,2 Mpa.