复合掺合料对水泥胶砂流动度和长期强度的影响

采用粉煤灰(F)、矿渣粉(Sl)、硅灰(Si)和石灰石粉(L)复合组成5种复合矿物掺合料,研究了复合掺合料的组成和掺量对水泥胶砂流动度、长期抗压强度和抗折强度的影响。结果表明:掺粉煤灰和石灰石粉的FSlL和FL复合掺合料流动性较好,流动度比达到110%以上;掺硅灰的FSlSi和SlSiL复合掺合料流动性较差,流动度比在80%左右;5种复合掺合料在30%、40%、50%掺量下,胶砂试件720 d抗压强度和抗折强度均达到纯水泥试件的110%~120%;FSlSi、FSl和FL复合掺合料随着掺量的提高,长龄期胶砂抗压强度有所增加,抗折强度发展趋势与抗压强度相同;SlL和SlSiL复合掺合料随着掺量的提高,长龄期胶砂抗压和抗折强度均略有下降。

Effect of Composite Admixtures on Fluidity and Long-term Strength of Cement Mortar

Five kinds of composite admixtures were composed of fly ash(F),slag powder(Sl),silica fume(Si)and limestone powder(L)in varying proportions.The effects of composition and content of composite admixtures on fluidity,long-term compressive strength and flexural strength of cement mortar were studied.The research results show that the flow properties of FSlL and FL composite admixtures that contain fly ash and limestone powder are superior,and the fluidity ratio is above 110%.The flow properties of FSlSi and SlSiL composite admixtures with silica fume are inferior,and the fluidity is about 80%.The compressive strength and flexural strength of 720 d mortar specimen with five kinds of composite admixtures are 110%~120%of those of pure cement specimen when the dosages of composite admixtures separately are 30%,40%and 50%.With the increase of the content of FSlSi,FSl or FL,the long-term compressive strength of mortar increases,and the development trend of flexural strength is the same as that of compressive strength.As the increase of the content of SlL and SlSiL,the long-term compressive strength and flexural strength of mortar decrease slightly.