基于渗流理论的矿物掺合料效应分析方法

Analysis Method of Admixture Effect with Porosity-strength Model Based on Pore Percolation

根据基于渗流理论的孔隙率强度模型的物理意义,认为利用矿物掺合料硬化浆体数据拟合的模型参数值以及不同龄期孔隙率-强度数据点与纯水泥拟合曲线的偏差,可分析矿物掺合料的掺合料效应。对钢渣、矿渣和粉煤灰等的掺合料效应分析表明,矿物掺合料均能在一定程度上提高孔在三维空间渗流临界点的水泥石强度σ0,体现了其微集料效应。因不同矿物掺合料的二次水化反应能力差异,在长短不一的水化早期内使其硬化浆体强度较纯水泥有一定下降,体现出不同程度的强度负效应,而在水化后期,各矿物掺合料均体现出一定的强度正效应。

Based on physical meaning of porosity-strength model, the errors between the porosity-strength data regression curve of pure cement paste and porosity-strength data of paste with mineral admixtures are discussed. Positive error shows that mineral admixture has positive effect on cement-based materials strength, and negative error shows that mineral admixture has negative effect. The paper indicates that those errors reflect influence of mineral admixture on properties of cement-based mate- rials. Mineral admixture effect can be analysed with those errom and parameter of porosity-strength model. Moreover, the paper discusses admixture effect of steel-making slag, slag and fly ash at different hydration stage in 180 days. The results indicate that all mineral admixtures can increase paste strength σ0 various degrees at the critical point of pore percolation in three dimen- sions, which embody macro aggregate effect of mineral admixture. Different mineral admixture displays different degree nega- tive effect in different length hydration early age due to the distinction in the power of the second hydration, at the same time they displays different degree positive effect at hydration later age.