摘要
选择低碱性速凝、早强物质,采用外加剂复配的方法,通过对水泥凝结时间,强度检验的手段,进行了正交试验,确定了一种喷射混凝土用低碱性速凝外加剂的配方。通过试验结果可以得出,Al2(SO4)3掺量在2%～4%之间时,随着掺量增大,初凝时间和终凝时间变短,掺量为4%时,初凝为14分,终凝25分;K2SO4掺量在2%～4%之间可以缩短水泥凝结时间,掺量为4%时,初凝为12分,终凝23分,当其掺量超过4%时,后期强度会下降;NaF的速凝效果十分显著,当掺量只有0 2%时就可以使水泥的初凝时间控制在5分钟,终凝控制在10分钟。与传统的高碱性外加剂不同,低碱性速凝剂可显著提高喷射混凝土早期强度,1天强度可达9 6MPa,而且后期强度发展良好,28天强度达到45 5MPa。
Orthognal test was made through choosing low-alkali flash setting and early-strength materials,compounding with admixture and checking the cement setting time and strength.And the mixing method of shotcrete with low-alkali accelerating admixture was carried out.The result shows that the more the Al_2(SO_4)_3,the shorter time for prehardening and final setting;the more KSO_4,the shorter time for setting,while the amount is over 4% poststrength can be lower;0.2% NaF can control the prehardening time in 5 minutes and final setting time in 1 minute.Different from the high-alkali admixture,the low-alkali accelerating admixture can improve concrete early strength apparently from 9.6MPa in the first day to 45.5MPa in the 28th day.
出处
《混凝土》
CAS
CSCD
北大核心
2005年第2期59-62,共4页
Concrete
关键词
喷射混凝土
速凝
早强
shotcrete
flash set
early-strength
