组合膨胀剂对风电灌浆料早期膨胀性能的影响

Effect of Composite Expansive Agent on Early-Age Expansion Properties of Cementitious Grouting Material for Wind Power Project

基于改进的竖向膨胀率(εv)测试方法,获得了高强风电灌浆料0~24 h、1~7 d的εv发展全曲线;并研究了掺合料比例及组合膨胀剂比例对灌浆料εv、流动度、力学强度的影响.结果表明:灌浆料0~24 h竖向膨胀率曲线呈“四阶段”特征;在0%~20%掺量范围内提高硅灰掺量,灌浆料流动度下降,0~24 h内εv曲线峰值先增大后减小;塑性膨胀剂(PEA)对24 h内εv发展起主导作用,复掺氧化钙-硫铝酸钙双源膨胀剂(HP-CSA)后,εv峰值减小,24 hεv下降、3 hεv增大,有利于控制24 h与3 h的εv差值;在1~7 d内,0.03%掺量的PEA即可促进HP-CSA膨胀效能的发挥,6%以上掺量的HP-CSA可较好补偿竖向自收缩变形而获得净膨胀灌浆料;PEA与HP-CSA组合,可发挥时间上接力、效果上协同的膨胀调控作用,可分阶段、按需设计,从而实现对灌浆料7 d内竖向膨胀率的精细调控;随组合膨胀剂掺量增加,灌浆料初始和30 min流动度无明显变化,28 d抗压强度先增大后减小;在本文研究范围内,0.06%PEA+6%HP-CSA是最优掺量组合.

Based on an improved vertical expansion rate(εv)testing method,the development ofεv of high-strength cementitious grouting material for wind power project within 0-24 hours and 1-7 days was obtained.The effects of the proportions of mineral admixtures as well as expansive agents onεv,fluidity and mechanical strength of grouting material were experimentally investigated.Results show that a typical developing characteristic with“four stages”is observed in the curves ofεv-time of grouting material during 0-24 hours.With the increase of silica fume percentage in the range of 0%-20%,the fluidity of grouting material decreases gradually,and the peak value ofεv firstly increases and then decreases from casting to 24 hours.Plastic expansive agent(PEA)dominants the development ofεv within 24 hours.Furthermore,calcium sulphoaluminate-calcium oxide expansive agent(HP-CSA)is added,the peak value ofεv decreases,the 24 h-value decreases,and the 3 h-value increases,which is beneficial to the control of the difference between the 24 h-value and 3 h-value.During the age of 1-7 days,the expansive efficiency of HP-CSA can well be promoted by PEA with addition of 0.03%.And the vertical autogenous shrinkage can generally be“compensated”by HP-CSA with the addition percentage not less than 6%,resulting in a grouting material with a net expansion during the period either 0-24 hours or 1-7 days.Relay effect in time and synergistic effect in outcome on expansion regulation for the grouting material are observed when PEA and HP-CSA composite are used,and if an appropriate dosage is found,a fine regulation onεv is well achieved in stages within 7 days.In addition,with the increase of the composite expansive agent,the initial and 30 mins values of fluidity of the grouting material shows little change,and the compressive strength at 28 days first increases and then decreases.Within the scope of this study,PEA at 0.06%and HP-CSA at 6%is comprehensively the optimal dosage composite.