利用粒料裹浆厚度推演混凝土配比设计方法

New Approach to Design Concrete Mix Proportions by Coating Thickness of Aggregates

利用裹浆厚度设计混凝土配比的方法,以致密配比逻辑为基础,配合富勒曲线,求解了各尺寸粒料之混合比例;估算了各粒料之总表面积及裹浆厚度,以计算总浆体体积;根据总浆体体积,代回致密配比逻辑,求解了各混凝土组成材料用量.这种方法可修正原致密配比逻辑中填塞堆积试验及放大浆量VP=nVV之设计方式,对混凝土性质做了更精确的定量分析.

Total paste volume of concrete consists of the void between aggregates（VV） and the lubricating paste for workability i.e.the surface area of aggregates（S） multiplied by coating thickness（t）.So the total paste volume of concrete can be described as V_P=V_V＋St.This study presents a new approach to design concrete mix proportions by coating thickness of aggregates.This approach is on the basis of densified mixture design algorithm（DMDA） and adopts the Fuller＇s curve to deduce a new method to design concrete mix proportions.There are three main processes in this approach：（1）use least squares method to draw near Fuller＇s curve and calculate the proportions of blended aggregates;（2）estimate the surface area of blended aggregates and coating thickness and calculate the total paste volume in accordance with the above estimated results;（3）according to the calculated total paste volume and DMDA the amount of constituted materials in concrete is calculated.This new approach will modify the design method i.e.the packing test and enlarging paste amount（VP=nVV） of original DMDA.The properties of concrete will be made more quantitative through this approach.