The effects of biomass ash on soil evaporation and cracking

Abstract

Biomass materials have been rapidly used in generating power, heating, and other industrial applications; the remains from the combustion of biomass materials, biomass ash, are being produced in large quantities rapidly. Accordingly, a method of consuming biomass ash, expanding new applications, and achieving resource utilization is urgently required. This research studies the basic properties of adding biomass ash in soils by examining the effects of water evaporation and the development of shrinkage cracks in soils. Laboratory evaporation tests have been carried out on soil samples with different quantities of biomass ash. The loss of mass is recorded to evaluate the effect of biomass ash on the behavior of water evaporation in the soil. Image processing technology and fractal theory are used to quantitatively analyze the development of shrinkage cracks on the soil surface. The results show that biomass ash can effectively reduce evaporation and crack development in soil. With increases in the biomass ash content, although the difference of residual water content is small, the evaporation time is increased with decreasing crack ratio. The addition of biomass ash greater than 5% has a significant impact (p ≤ 0.05) on soil evaporation, and the addition greater than 2.5% has a significant impact (p ≤ 0.05) on soil cracking. The time of evaporation with biomass ash addition amount of 2.5%, 5%, 10%, 15%, and 20% increased by 10%, 22%, 32%, 43%, and 49% in turn, the crack ratio of which decreased by 12%, 42%, 65%, 72%, and 74%, respectively, over control samples.