摘要
为调控混凝土早期收缩开裂,探究膨胀剂和高吸水树脂内养护剂组合对混凝土早期收缩的调控规律及对力学强度的影响,本研究以膨胀剂和内养护水均占胶凝材料总质量的0、3%、6%、9%组合掺入的混凝土作为对象,测试了早期自由变形、抗压和劈裂抗拉强度以及干燥失水率。结果表明:随着膨胀剂和内养护水组合掺量的增加,前3 d龄期内的混凝土自由变形曲线由“W”型逐渐向“L”型演变,混凝土28 d内自收缩和干燥收缩均被调控下降,直至掺量9%组密封养护下产生1 310×10^(-6)的明显膨胀;但各组的净干燥收缩仍不能根除,同时28 d龄期的力学强度逐渐降低。混凝土3~28 d内净干燥收缩和干燥失水率基本呈线性相关。基于试验结果,确定6%组合掺量在本研究中相对较优。
In order to regulate the early shrinkage and cracking of the concrete, the influence of combined expansive agent and internal curing water of super absorbent polymer(SAP) on the regulation laws of early shrinkage and mechanical strength of concrete were investigated in this study. Specifically, this study analyzed the concrete in which the expansive agent and internal curing water with a combined dosage accounting for 0%, 3%, 6%, and 9% of the total mass of the binding material are added. In addition, the study tested the early free deformation, compressive strength, splitting tensile strength, and drying-induced water loss rate. The results show that as the combined dosage of the expansive agent and internal curing water increases, the free deformation curve of concrete in the first three days gradually evolves from W-shaped to L-shaped, and the concrete autogenous and drying shrinkage decreases gradually in 28 days until an expansion up to 1 310×10^(-6)is noticed in the group with a combined dosage of 9% under sealed curing condition. However, the net drying shrinkage of all groups cannot be eliminated, and the mechanical strength of the concrete decreases gradually in 28 days. Furthermore, the drying-induced water loss rate is linearly correlated to the net drying shrinkage of concrete from three days to 28 days. According to experimental results, the group with a combined dosage of 6% is optimal in this study.
作者
李威
韩宇栋
岳清瑞
丁小平
孟兮
党玉栋
LI Wei;HAN Yudong;YUE Qingrui;DING Xiaoping;MENG Xi;DANG Yudong(Central Research Institute of Building and Construction Co.,Ltd.,MCC Group,Beijing 100088,China;Research Institute of Urbanization and Urban Safety,University of Science and Technology Beijing,Beijing 100083,China;Yunnan Institute of Building Research Co.,Ltd.,Kunming 650223,China)
出处
《工业建筑》
CSCD
北大核心
2022年第10期115-121,共7页
Industrial Construction
基金
国家自然科学基金项目(52178263)
北京市科技新星计划(Z201100006820024)
中冶建筑研究总院有限公司重大课题(YCK2017Ky01)。
关键词
混凝土
收缩
膨胀剂
内养护
高吸水树脂
组合调控
concrete
shrinkage
expansive agent
internal curing
SAP
combined control
