摘要
粉煤灰(FA)和硅灰(SF)是2种产量较大的工业废料,用适量粉煤灰和硅灰复掺替代水泥(C)能够有效改善水泥基材料的性能。本文探究了15%、20%、25%粉煤灰和5%、10%、15%硅灰复掺后等质量替代水泥对砂浆性能的影响,结果表明:粉煤灰掺量的增加能够改善砂浆的和易性,提高砂浆的扩展度,延长凝结时间;硅灰则相反,随着硅灰掺量的增加,会提高砂浆的粘稠度,降低砂浆的流动性能,缩短砂浆的凝结时间,且粉煤灰和硅灰复掺会显著缩短砂浆初凝和终凝时间的间隔。掺入硅灰和粉煤灰对砂浆力学性能的影响显著,硅灰掺量的增加能够增强砂浆的早期和后期强度,但当粉煤灰掺量超过15%时,砂浆的抗折强度和抗压强度始终小于对照组砂浆,且当粉煤灰和硅灰复掺的掺量超过30%时,砂浆的抗压强度出现逐渐下降的趋势,因此,粉煤灰的掺量不宜大于15%,粉煤灰和硅灰复掺的掺量不宜超过30%。利用扫描电镜观测砂浆微观形貌,发现粉煤灰和硅灰的掺入能够消耗Ca(OH)_(2)晶体,增加砂浆的密实度,但过量的粉煤灰会导致基体结构疏松,降低砂浆的强度。
Fly ash(FA)and silica fume(SF)are two types of industrial waste with large production volumes.Using an appropriate amount of fly ash and silica fume to replace the amount of cement(C)can effectively improve the performance of cement-based materials.This article explores the effects of using 15%,20%,25%fly ash and 5%,10%,15%silica fume as substitutes for cement on the properties of mortar.The results show that increasing the amount of fly ash can improve the workability of mortar,enhance its expansion,and prolong its setting time;on the contrary,with the increase of silica fume content,the viscosity of mortar will be increased,the f lowability of mortar will be reduced,and the setting time of mortar will be shortened.Besides,the combination of fly ash and silica fume will significantly shorten the interval between the initial and final setting times of mortar.The inf luence of adding silica fume and fly ash on the mechanical properties of mortar is significant.Increasing the dosage of silica fume can enhance the early and later strength of mortar.However,when the dosage of fly ash exceeds 15%,the f lexural strength and compressive strength of mortar is always lower than that of the control group mortar.Moreover,when the dosage of fly ash and silica fume exceeds 30%,the compressive strength of mortar gradually decreases.Therefore,the dosage of fly ash should not exceed 15%,and the dosage of fly ash and silica fume should not exceed 30%.By using scanning electron microscopy to observe the microstructure of mortar,it is found that the addition of fly ash and silica fume can consume Ca(OH)_(2) crystals,increase the compactness of mortar,but excessive fly ash can lead to loose matrix structure and reduce the strength of mortar.
出处
《混凝土世界》
2025年第6期27-31,共5页
China Concrete
关键词
粉煤灰
硅灰
水泥基材料
力学性能
微观机理
Fly ash
silica fume
cement-based materials
mechanical properties
microscopic mechanisms
