五乙酰葡萄糖对氧化钙膨胀剂早期自由变形的影响

Effect of Penta-Acetyl Glucopyranose on Early Free Deformation of Calcium Oxide Based Expansion Agent

研究了五乙酰葡萄糖对掺加氧化钙膨胀剂的水泥净浆,自加水开始30 min后的早期自由变形,其延长了水泥净浆的凝结时间,增大了早期的膨胀变形速率及膨胀变形。相比于基准净浆膨胀变形,0.2%、0.3%和0.4%掺量的五乙酰葡萄糖分别提升了净终浆凝后48 h膨胀变形22.8%、41.5%和73.1%。通过色谱方法定量测试了五乙酰葡萄糖在纯水和pH=13.5的碱性水溶液中的水解历程,五乙酰葡萄糖在纯水中稳定,在碱性溶液中迅速水解,释放出葡萄糖。五乙酰葡萄糖在碱性条件下水解释放出葡萄糖可能是影响水泥水化及膨胀剂早期变形作用的主要原因。

The effect of penta-acetyl glucopyranose on early free deformation of cement paste with calcium oxide based expansive agent after 30 min of water addition is studied.The setting time of cement paste is prolonged,and the early expansion deformation rate and expansion deformation are increased.Compared with the deformation of the comparing paste,the free deformation of 48 h after final setting is increased by 22.8%,41.5%and 73.1%with 0.2%,0.3%and 0.4%penta-acetyl glucopyranose,respectively.The hydrolysis process of penta-acetyl glucopyranose in pure water and alkaline solution with pH=13.5 is quantitatively tested by the chromatographic method.Penta-acetyl glucopyranose is stable in pure water.But it can hydrolyze rapidly in alkaline solution and release glucose.Glucose generated from penta-acetyl glucopyranose under alkaline conditions may be the main reason affecting cement hydration and early deformation of expansive agent.