约束条件下外掺MgO混凝土的强度与膨胀应力

Strength and Expansive Stresses of Concrete with MgO Type Expansive Agent under Restrain Conditions

摘要:

研究了掺0%，5%，8%，12%(质量分数)MgO混凝土的自由膨胀、约束膨胀及其在约束条件下的抗压强度和膨胀应力.结果表明：混凝土的自由膨胀随着MgO掺量的增加而增大，560d龄期时，MgO掺量为0%，5%，8%和12%的混凝土其最大膨胀量分别为-33×10-6，90×10-6，230×10-6和320×10-6.MgO掺量相同时，三维约束试件强度＞二维约束试件强度＞自由试件强度.三维约束条件下，混凝土膨胀应力随MgO掺量的增加而增大；在三维方向上膨胀应力大小规律为pc,x＞pc,z＞pc,y；膨胀应力随养护龄期的延长而增加并在一定龄期内趋于稳定.

Abstract:

Free expansion, three direction expansion stresses and strength of concrete under restraints were investigated. Results indicate that free expansions of concrete with 0%，5%，8% and 12%(by mass) MgO are -33×10-6，90×10-6，230×10-6 and 320×10-6 at 560 d. The strength of concrete with MgO restrained in three dimension is higher than that restrained in two dimension, the latter is higher than that of concrete unrestrained. Under the three dimensional restraints, the expansive stresses of concrete increase with increase of MgO type expansive agent. What is more, the specimen size has an obvious effect on the expansive stresses of concrete：pc,x＞pc,z＞pc,y. With the increase of curing age, the expansive stresses tend to be stable in the experiment.