摘要
收缩开裂是影响现代混凝土耐久性的主要因素。本文通过平板开裂试验、圆环开裂试验评定粉煤灰掺量与外加剂品种对混凝土开裂的影响。结果表明,适当掺入优质粉煤灰,对于早期塑性开裂具有一定的抑制作用,塑性收缩的开裂总面积下降,混凝土的抗裂性提高;随粉煤灰掺量增大,圆环试件的开裂时间和裂宽均呈下降趋势。试验结果还表明:与其它几种外加剂相比,聚羧酸高效减水剂与2%减缩剂复配后对抑制混凝土早期塑性开裂和后期干燥开裂均具有显著效果。
Shrinkage and cracking are the primary factors influencing the durability of modern concrete.In this paper,the effects of the dosage of fly-ash and the kinds of chemical additives on the concrete cracking properties are tested by the ring testing method and slab testing method.The experimental results show that fly-ash with the proper dosage could inhibit the plastic cracking of concrete,the total areas of plastic cracking decrease and the anti-cracking grade of concrete is improved.With the increase of fly-ash proportion,the cracking time and crack width of ring specimen decreased.Furthermore,compared with the other kinds of additives,the experimental results show that when the polycarboxylate superplasticizer with 2% SRA（by weight of cementitious materials） is added into concrete,there is obvious effects on the resistance to the plastic cracking at early age and drying cracking at later age of concrete.
出处
《混凝土与水泥制品》
北大核心
2011年第4期6-9,共4页
China Concrete and Cement Products
