减水剂掺量对水泥净浆及高强自密实混凝土的影响

Influence of water reducing agent content on cement paste and high strength self compacting concrete

为探究减水剂掺量对水泥净浆及高强自密实混凝土的影响,在原材料保持一致的前提下,通过适当改变减水剂掺量,对水泥净浆流动度及经时损失和自密实混凝土扩展度及经时损失和抗压强度进行分析。结果表明,随着减水剂掺量的增加,减水剂分子起到了分散作用和空间位阻作用,使得水泥净浆和混凝土拌合物的流动性增加,扩展度经时损失变化不大;混凝土在使用前需确定好减水剂的最佳掺量,从而使新拌混凝土获得最佳和易性能和力学性能;应控制水泥、粉煤灰、砂石等原材料的关键性能指标,关注外加剂与胶凝材料之间的适应性,及时调整混凝土配合比中外加剂掺量或配方。

In order to explore the influence of the content of water reducing agent on cement paste and high-strength self compacting concrete,on the premise of keeping the same raw materials,this paper analyzes the fluidity and time loss of cement paste and the expansion,time loss and compressive strength of self compacting concrete by changing the content of water reducing agent.The results show that with the increase of the content of water reducing agent,the water reducing agent molecules play the role of dispersion and steric hindrance,which increases the fluidity of cement paste and concrete mixture,and the expansion loss changes little over time.The optimum content of water reducing agent should be determined in advance,so as to obtain the best workability and mechanical properties of fresh concrete.It is necessary to control the key performance indicators of raw materials such as cement,fly ash and sand,pay attention to the adaptability between admixtures and cementitious materials,and timely adjust the amount or formula of admixtures in the concrete mix proportion.