早强剂对C30喷射混凝土抗压强度的影响

Influence of early strength agent on the compressive strength of C30 shotcrete

研究了不同早强剂(元明粉、硫酸铝、七水硫酸镁、硝酸钙、亚硝酸钠、硫氰酸钠和CSH晶种)单掺及复掺对C30喷射混凝土抗压强度的影响。结果表明:不同厂家CSH晶种对C30喷射混凝土各龄期抗压强度的作用效果有所差异,其中,CSH晶种2#对抗压强度的提高效果最好;通过优化配合比,元明粉可以提高试件的早期抗压强度,且28 d抗压强度发展较好;硝酸钙、亚硝酸钠、硫氰酸钠单掺及与其他早强剂复掺对C30喷射混凝土8 h抗压强度的提高效果并不明显,甚至会降低喷射混凝土的抗压强度。

The effect of different early strength agents(sodium sulfate,aluminum sulfate,magnesium sulfate heptahydrate,calcium nitrate,sodium nitrite,sodium thiocyanate,and CSH crystal seed)on the compressive strength of C30 shotcrete was studied by single and compound addition.The results show that the effect of CSH crystal seed from different manufacturers on the compressive strength of C30 shotcrete at different ages varies,among which CSH crystal seed 2#has the best effect on improving compressive strength.By optimizing the mix proportion,the early compressive strength of the specimens can be improved by using sodium sulfate,and the 28 d compressive strength development is better.The effect of adding calcium nitrate,sodium nitrite,sodium thiocyanate alone or in combination with other early strength agents on the 8 h compressive strength of C30 shotcrete is not significant,and may even reduce the compressive strength of shotcrete.