Experimental Research on Low Cost Paste Filling Material

摘要

Crushed coal gangue as coarse aggregate, and fly ash replaced partial cement as cementing material were used to prepare low cost paste filling material. The effects of aggregate with high content of clay on compressive strength, collapsed slump and bleeding rate were investigated. The best formula for markedly improving the compressive strength through adjusting the aggregate grading was proposed, it included 70% D=16-20mm and 30% D=10-16mm aggregates. The usage of fly ash as cementing material reduced the filling cost. The compressive strength kept increasing when the ratio of fly ash was less than 20%, however rapidly decreased while it was 40%. The collapsed slump and compressive strength were greatly reduced by clay existed in fly ash and riversand. The mixing water consumption was notablely increased in order to ensure collapsed slump achieved the existing requirement, simultaneously the 1-day compressive strength reduced and 28-day compressive strength didn't change significantly.