摘要
通过研究氧化镁掺量为0、4%、6%、8%混凝土的劈裂抗拉强度、变温历程下的约束应力发展,并结合成熟度理论和数据拟合计算混凝土变温历程下的等效龄期,评价混凝土的开裂敏感性。结果表明,掺4%、6%氧化镁可提高混凝土的劈裂抗拉强度,掺8%氧化镁可提高混凝土的早期劈裂抗拉强度,但不利于后期劈裂抗拉强度发展;温度-应力试验表明,掺氧化镁可以提高混凝土的抗裂性能,但开裂温度和开裂应力的定量评价结果存在差异;开裂敏感度综合考虑了混凝土温度历程和劈裂抗拉强度发展,其作为评价指标更加准确,氧化镁掺量为4%、6%、8%的混凝土开裂敏感度较基准组分别减小了4.6、5.0、1.8个百分点。
By adding 0,4%,6%,8%magnesium oxide to concrete,splitting tensile strength and restraint stress development under varying temperature history were studied.Combined with maturity theory and data fitting,the equivalent age of concrete under changing temperature history was calculated.It evaluated the cracking susceptibility of concrete.The results showed that the split-ting tensile strength of concrete can be improved by adding 4%and 6%magnesium oxide.The early tensile strength of concrete could be improved by adding 8%magnesium oxide.However,it is not conducive to the development of later splitting tensile strength.The evaluation index of temperature-stress test showed that adding magnesium oxide could improve the crack resistance of concrete.There were differences in the quantitative evaluation results of cracking temperature and cracking stress.Cracking suscep-tibility considering concrete temperature history and tensile strength development.It was more accurate as an evaluation index.Compared with the reference group,the cracking sensitivity of concrete with 4%,6%and 8%MgO decreased by 4.6,5.0 and 1.8percentage points respectively.
作者
秦哲焕
朱国军
刘杰胜
纪宪坤
刘拼
QIN Zhehuan;ZHU Guojun;LIU Jiesheng;JI Xiankun;LIU Pin(Wuhan Sanyuan Special Building Materials Co.Ltd.,Wuhan 430070,China;Wuhan Polytechnic University,Wuhan 430070,China)
出处
《新型建筑材料》
2023年第2期11-14,41,共5页
New Building Materials
关键词
成熟度理论
等效龄期
劈裂抗拉强度
温度应力试验机
开裂敏感度
maturity theory
equivalent age
splitting tensile strength
temperature stress testing machine
cracking sensitivity
