再生粗骨料混凝土强度预测模型研究

Study of Strength Model for Recycled Coarse Aggregate Concrete

再生骨料与天然骨料相比,具有密度较小、吸水率和压碎指标较大的突出特点,且现有的关于再生粗骨料混凝土强度的配合比设计方法,在如何考虑水胶比、再生粗骨料性质以及再生粗骨料替代率等因素的影响方面还没有形成系统全面的设计理论。通过对104组再生粗骨料混凝土力学性能试验数据库的分析,建立了基于普通混凝土配合比设计方法,兼顾水胶比、再生粗骨料压碎率以及再生粗骨料替代率的再生粗骨料混凝土强度经验模型,经检验该经验模型的预测误差在6.5%以内,为再生粗骨料混凝土配合比设计提供强度参考。

Compared with the natural aggregate,the recycled aggregate has the outstanding characteristics of smaller density,larger water absorption and crushing index.A comprehensive mix design theory of recycled coarse aggregate concrete,concerning the effects of the mix proportion design method,the water/cement ratio,the properties of the recycled coarse aggregate and the recycled coarse aggregate replacement rate,has not been formed systematically.Based on a regression analysis of the compression strength database of 104 groups of recycled coarse aggregate concrete（RAC）,which is designed on the basis of the normal concrete mix proportion design method,this paper developes an empirical strength model for recycled coarse aggregate concrete.The effects of the water to binder ratio,the recycled coarse aggregate crushing ratio and the recycled coarse aggregate replacement ratio on the strength of RAC are revealed in the model.A comparative analysis shows that the predictions made using the strength model are very accurate and the mean error is within 6.5%.This indicates that the empirical model can be used for the strength design of RAC.