摘要
为了评价内养护与膨胀剂复合作用对混凝土综合抗裂性能的改善效果，采用温度一应力试验法研究了在实际温度历程下受强约束状态时，掺高分子吸水树脂（SAP）和膨胀剂（UEA）的混凝土的温度一应力发展，并研究了SAP和UEA复掺对混凝土工作性、力学性能和长期变形性能的影响。结果表明：SAP和UEA复掺，增大了混凝土升温阶段的压应力，降低了降温阶段拉应力发展速率和混凝土的开裂温度，开裂温降提高了10℃以上，延长了混凝土的开裂时间。SAP和UEA复掺对混凝土工作性影响不明显，略微降低了混凝土的抗压强度。变形性能试验表明：SAP和UEA复掺使混凝土的极限拉伸值提高了10％～30％，混凝土的干燥收缩降低了10％～20％；14d水养护混凝土限制膨胀率在0．05％左右，转为恒温恒湿的空气中养护时，42d膨胀率在0．04％左右。因此，内养护与膨胀剂复合作用显著改善了混凝土的综合抗裂性能。
In order to evaluate the hybrid effect of internal curing and expansive agent （UEA） on the improvement of concrete complex crack resistance, the temperature and stress development of concretes with super absorbent polymer （SAP） and UEA were investigated via thermal stress tests. The experimental results show that the hybrid effect of SAP/UEA can increase the concrete pre-compressive stress in the heating stage and decrease the tensile stress development rate in the cooling stage. The cracking temperature of concretes with SAP/UEA reduces, the difference between the maximum temperature and the cracking temperature of the concretes with SAP/UEA is 10 ~C greater than that of the concretes without SAP/UEA, and the cracking time of concretes with SAP/UEA extends. Also, the hybrid effect of SAP/UEA has no significant effect on the concrete workability and can slightly decrease the cube compressive strength. According to the results of long-term deformation properties tests, the hybrid effect of SAP/UEA improves the concrete ultimate tensile elongation in the range from 10% to 30%, and reduces the concrete drying shrinkage in the range from 10% to 20%. The restrained expansion rate of concrete with SAP/UEA is 0.05% when the specimens are cured in water for 14 d, and the restrained expansion rate is still 0.04% in curing for 42 d at constant temperature and humidity. The results indicate that the hybrid action of internal curing and expensive agent could improve the concrete complex crack resistance.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2016年第2期189-195,201,共8页
Journal of The Chinese Ceramic Society
基金
国家自然科学基金项目(编号51438003
51378113)
中央级公益性科研院所基本科研业务费专项(Y415014)
关键词
内养护
膨胀剂
温度-应力试验
综合抗裂性
internal curing
expansive agent
thermal stress test
complex crack resistance
