再生植生混凝土基本性能影响研究

Influences on basic performance of recycled planting concrete

进行了系列设计孔隙率、水胶比、早期碳化养护工艺对再生植生混凝土的连续孔隙率、植生孔径、抗压强度和pH值影响试验研究,试验结果表明:设计孔隙率在21%~31%之间变化时,植生混凝土的抗压强度逐渐降低,在31%时,抗压强度仍可实现11.2 MPa,因此,设计孔隙率不宜超过31%,同时连续孔隙率和植生孔径可以满足标准要求;随着水胶比从0.21~0.31变化时,混凝土抗压强度逐渐降低,同时对连续孔隙率和植生孔径会产生一定的影响;随着硅灰取代率提高,抗压强度逐渐增高,最优取代率为9%,之后降低,同时混凝土的碱度逐渐降低,当硅灰取代率为9%时,pH值可降低至10.20;混凝土早期采取40%浓度、0.1 MPa加压碳化养护后混凝土强度增加,且采用标准方法测试的混凝土的pH值可以降低至9.13,混凝土原状块90 d浸渍液pH值可低至8.02,满足JC/T 2557《植生混凝土》的规定要求。

A series of experimental studies were conducted on the effects of designed porosity,water cement ratio,and early carbonization curing process on the continuous porosity,planting pore size,compressive strength,and pH value of recycled planting concrete.The experimental results showed that when the designed porosity varied between 21%and 31%,the compressive strength of planting concrete gradually decreased.And the compressive strength could still reach 11.2 MPa at 31%of designed porosity.Hence the designed porosity should not exceed 31%,and the continuous porosity and planting pore size could meet the standard requirements simultaneously.As the water cement ratio increased from 0.21 to 0.31,the compressive strength of concrete gradually decreased,and it also had a certain influence on the continuous porosity and planting pore size.As the replacement rate of silica fume increased,the compressive strength gradually increased.The optimal replacement rate was 9%,which followed by decrease.At the same time,the alkalinity of the concrete gradually decreased.When the replacement rate of silica fume was 9%,the pH value could be reduced to 10.20.After adopting a 40%concentration and 0.1 MPa pressure condition of carbonization curing method in the early stage of concrete,the strength of the concrete increased,and the pH value of the concrete could be reduced to 9.13 by standard test methods.The pH value of the immersion solution,for the original concrete block on 90 d,could be as low as 8.02,which meet the requirements of Chinese standard“Planting Concrete”(JC/T 2557).