β-hemihydrate phosphogypsum(HPG)was used to replace a part of cement to prepare hemihydrate phosphogypsum-red mud concrete,effectively increasing the comprehensive use of red mud(RM)and HPG in the concrete.The effect...β-hemihydrate phosphogypsum(HPG)was used to replace a part of cement to prepare hemihydrate phosphogypsum-red mud concrete,effectively increasing the comprehensive use of red mud(RM)and HPG in the concrete.The effects of different RM and HPG contents on the flow properties,water absorption and strengths of HPG-RM concretes were investigated.The appropriate content of HPG reduces the water resistance of red mud concrete,enhances the cohesion and water retention,and effectively filled the pores to decrease the degree of free water erosion.The optimal HPG content was 5%,10%,and 10%for red mud concretes with 30%,40%,and 50%RM,respectively.HPG content has more significant effects on the 28 d strengths of HPG-RM concretes.This consequence is accordant with the effect of HPG content on the pore size and pore size distribution from MIP results.The SEM and XRD results show that a large amount of SO_(4)^(2-)and Ca^(2+)from HPG promote the volcanic ash effect of RM generating more favorable hydration products.However,excessive HPG generates more Ettringite to inhibit the generation of calcium silicate and albite,causing cracks in the concrete and deteriorating performance.展开更多
基金Funded by the National Natural Science Foundation of China(Nos.52168027 and 12362011)the Guizhou Province Science and Technology Innovation Talent Team Project(No.CXTD[2023]022)the Guizhou Province Science and Technology Support Project(No.[2022]027)。
文摘β-hemihydrate phosphogypsum(HPG)was used to replace a part of cement to prepare hemihydrate phosphogypsum-red mud concrete,effectively increasing the comprehensive use of red mud(RM)and HPG in the concrete.The effects of different RM and HPG contents on the flow properties,water absorption and strengths of HPG-RM concretes were investigated.The appropriate content of HPG reduces the water resistance of red mud concrete,enhances the cohesion and water retention,and effectively filled the pores to decrease the degree of free water erosion.The optimal HPG content was 5%,10%,and 10%for red mud concretes with 30%,40%,and 50%RM,respectively.HPG content has more significant effects on the 28 d strengths of HPG-RM concretes.This consequence is accordant with the effect of HPG content on the pore size and pore size distribution from MIP results.The SEM and XRD results show that a large amount of SO_(4)^(2-)and Ca^(2+)from HPG promote the volcanic ash effect of RM generating more favorable hydration products.However,excessive HPG generates more Ettringite to inhibit the generation of calcium silicate and albite,causing cracks in the concrete and deteriorating performance.
