矿粉混凝土的自收缩性能

研究了普通矿粉(422m2/kg)与超细矿粉(730m2/kg)对混凝土自收缩的影响。结果表明:①在同水胶比条件下,矿粉可降低混凝土早期(3d)自收缩,但增加后期(90d)自收缩;其影响程度与矿粉掺量和混凝土水胶比有关;②与普通矿粉(422m2/kg)相比,同条件下的超细矿粉(730m2/kg)混凝土早期(3d)自收缩显著增加;③同标号(f28)条件下,普通掺量(20%-35%)矿粉对混凝土早期(3d)自收缩影响不大,但对后期(90d)自收缩有一定负面影响。大掺量矿粉混凝土(50%)的早期与后期自收缩均显著增加。

AUTOGENOUS SHRINKAGE OF CONCRETES WITH GROUND SLAG

In this paper, the influence of ordinary ground slag and super finely ground slag on the autogenous shrinkage of conerete were studied. The results show that: ①Under the condition of the same water-binder ratio, the autogenous shrinkage of concrete at earlyage may be decreased by ground slag addition, but may be increased at later age. The influence extent is related to the contents of ground slag and water-binder ratio; ② The autogenous shirinkage of concrete with super finely ground slag is increased obviously at early age compared with concrete with ordinary ground slag under the same condition;③Compared with the reference concrete with the same strength, the autogenous shirinkage of concrete with 25 ~ 30 percent ground slag are about the same at early age, but at later age, the disadvantageous influence of ground slag on autogenous shrinkage of concrete is presented. The autogenous shrinkage of concrete with 50 percents ground slag are increased marked- ly.