再生骨料生态混凝土预测模型抗压强度试验研究

Experimental study on compressive strength of prediction model of eco-concrete with recycled aggregate

通过制备不同水灰比、骨料粒径、再生骨料取代率的生态混凝土,研究了再生骨料生态混凝土的抗压强度及其影响因素,并构建抗压强度表达式。结果表明:当水灰比为0.25~0.35时,脆性多孔材料孔隙率与强度关系式可适用于生态混凝土;当孔隙率介于20%~30%时,水泥净浆强度对生态混凝土抗压强度有较大影响,实际孔隙率可由目标孔隙率和水泥净浆强度较准确地表达;当目标孔隙率一定时,生态混凝土抗压强度随骨料粒径的增大而提高;再生骨料与水泥净浆的界面过渡区处易发生受压破坏;当再生骨料取代率大于25%时,生态混凝土的抗压强度随再生骨料取代率的升高而降低。所建立的抗压强度预测模型能够较好地反映出各因素对生态混凝土抗压强度的影响规律,可适用于水灰比为0.25~0.35且孔隙率介于20%~30%的再生骨料生态混凝土。

The compressive strength and influencing factors of recycled aggregate eco-concrete were systematically studied,and the expression of compressive strength was attempted to be constructed by preparing the eco-concrete with different water-cement ratio,aggregate size and replacement rate of recycled aggregate. The results show that when the water-cement ratio is 0. 25-0. 35,the relationship between porosity and strength of brittle porous materials can be applied to eco-concrete. When the porosity is between 20% and 30%,the strength of cement paste has a great influence on the compressive strength of eco-concrete. The actual porosity can be accurately expressed by the target porosity and the strength of cement paste. When the target porosity is fixed,the compressive strength of eco-concrete increases with the increase of aggregate size. The interface transition zone between recycled aggregate and cement paste is prone to compressive damage. When the replacement rate of recycled aggregate is more than 25%,the compressive strength of eco-concrete decreases with the increase of replacement rate of recycled aggregate. The prediction model of compressive strength constructed in this paper can well reflect the influence of various factors on the compressive strength of eco-concrete,and can be applied to eco-concrete with recycled aggregate with water-cement ratio of0. 25-0. 35 and porosity of 20%-30%.