再生混凝土Bolomey公式的修正

Modification of the Bolomey Formula in Recycled Aggregate Concrete

摘要:

引入再生粗骨料取代天然粗骨料所产生的附加用水量这一概念，将再生混凝土单位用水量拆分为“净用水量+附加用水量”.在再生骨料取代率RRCA（质量分数）分别为0%，20%，40%，60%，80%和100%时，保持再生混凝土工作性基本一致的条件下，根据混凝土不同单位用水量设计10组混凝土配合比，研究再生混凝土灰水比和净灰水比与强度的关系.结果表明：再生粗骨料取代率R与再生混凝土粗骨料吸水率wCA和表观密度ρCA均存在良好的线性关系；再生混凝土强度灰水比及强度净灰水比关系均符合Bolomey公式；利用再生混凝土强度灰水比及强度净灰水比回归系数之间的量化关系，推导出用再生混凝土粗骨料吸水率wCA或表观密度ρCA修正的再生混凝土Bolomey公式，为再生混凝土配合比设计提供较为简便的计算公式.

Abstract:

Additional water consumption produced by adding recycled coarse aggregate to substitute part or all of natural coarse aggregate was introduced as a concept, the unit water consumption in recycled aggregate concrete was divided into two parts：net water consumption and additional water consumption. Ten groups of concrete with different proportions(by mass) were designed according to the different unit water consumption, which kept the workability of concrete almost the same when the recycled coarse aggregate replacement percentages(by mass) were 0%, 20%, 40%, 60%, 80% and 100%,respectively. The results show that there are good linear relations between the recycled coarse aggregate replacement percentages R and water absorption wCA or apparent density ρCA of coarse aggregate. Both the relation between compressive strength and cement to water ratio of concrete and the relation between compressive strength and net cement to water ratio of concrete are in accordance with Bolomey formula. Using the regression coefficients of quantitative relation between the compressive strength and cement to water ratio of concrete and the relation between compressive strength and net cement to water ratio of concrete, the Bolomey formula was modified by the water absorption wCAor apparent density ρCA of coarse aggregate to supply the recycled aggregate concrete proportion with an easier formula.