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为了提高混凝土的早期抗裂性能,使用了不同种类的减水剂.采用平板法和温度应力试验法,研究了2种不同分子结构的聚羧酸减水剂和1种缓凝型萘系减水剂对混凝土早期抗裂性能的影响.结果表明,与萘系相比,聚羧酸减水剂并非一定能提高混凝土的早期抗裂性能,这与聚羧酸的分子结构有关.早期塑性抗拉强度和动弹性模量较高,将有利于抗裂,在此前提下,较低的水化热也有利于避免裂缝的产生.温度应力试验法与平板法结合可综合反映混凝土的干缩应力和水化热温度应力随时间的演化.
In order to improve the early cracking resistance of concrete, different types of superplasticizers were used.According to the plate method and the thermal stress test, two kinds of polycarboxylate superplasticizers with different molecular structure and one kind of retarding naphthalene- The results showed that compared with naphthalene, the polycarboxylate superplasticizer does not necessarily improve the early cracking resistance of concrete, which is related to the molecular structure of polycarboxylic acid. The early plasticity High tensile strength and dynamic modulus of elasticity will be conducive to crack, under the premise of a lower heat of hydration is also conducive to avoid the generation of cracks .Thermal stress test method and the combination of flat-panel method can be a comprehensive reflection of concrete shrinkage Stress and hydration Thermal stress evolution over time.