浆体新拌性能与透水混凝土硬化性能的相关性

Correlation between Fresh Paste Properties and Hardened Paste Performances of Pervious Concrete

使用减水剂和增稠剂配制了不同新拌状态的透水混凝土,考察了透水混凝土浆体新拌性能(流动性、黏聚性)与其硬化性能(抗压强度、透水系数、孔隙率)之间的相关性,并深入分析浆体新拌性能与其流变参数之间的关系.结果表明:随着浆体流动度的提高,浆体易向下流动,透水混凝土沿竖直方向的孔隙率递减,造成其透水性能下降;提高浆体黏聚性有助于其稳定包裹骨料,从而改善透水混凝土孔隙结构均匀性;使用减水剂和增稠剂能够同时提高浆体的流动性和黏聚性,使其在较低的屈服应力下获得较高的塑性黏度,可以增加透水混凝土浆体流动过程中的阻力,降低流速,既使透水混凝土具有良好的工作性能,又使浆体能够良好地与骨料粘结,不发生沉底堵孔现象.

Poly-carboxylate superplasticizer（PCA）and viscosity modifier（VMA）were used to prepare pervious concrete with different fresh conditions.The correlation between fresh paste properties（fluidity and cohesion）and hardened paste performances of pervious concrete（compressive strength,hydrological permeability and porosity）was studied.A further rheological investigation was also conducted to reveal a better understanding of the fresh paste in pervious concrete.The results show that,as the fluidity increases,the paste flows downwardly,leading a descending porosity along vertical direction.It helps to achieve a better porosity distribution uniformity by improving the cohesion of pervious concrete.The fluidity and cohesion of paste could be increased simultaneously,which yields a higher plastic viscosity and a lower yield stress when PCA and VMA are used at the same time.The flow velocity of paste is thus decreased sharply with no significant impact on bonding performance between paste and aggregate.Pervious concrete with the specific rheological properties shows a practicable workability and uniform pore structure.