掺红砖微粉地聚物再生混凝土基本力学性能研究

Study on basic mechanical properties of geopolymer recycled concrete with red brick powder

以再生粗骨料取代率、红砖微粉掺量作为变量,设置25组试验,对地聚物混凝土的再生粗骨料取代率r_(1)、红砖微粉-粉煤灰取代率r_(2)、红砖微粉-矿渣取代率r_(3)与坍落度、立方体抗压强度f_(cu)、劈裂抗拉强度f_(ts)、圆柱体轴心抗压强度f_(c)、弹性模量E_(c)、泊松比μ之间的关系进行研究。试验结果表明:随取代率r_(1)增大,坍落度先降低后升高,混凝土各项力学性能逐渐下降,且当r_(1)≤50%时,f_(cu)均大于40 MPa;随取代率r_(2)增大,坍落度降低,混凝土力学性能逐渐上升,r_(2)=20%时强度提高10.68%~14.52%;随取代率r_(3)增大,坍落度降低,r_(1)≤50%时力学性能先上升后下降,r_(3)=10%时强度提高5.39~9.99%,r_(1)较大时r_(3)对力学性能存在不利影响。

Taking the replacement rate of recycled coarse aggregate and the content of red brick powder as variables,25 groups of tests were set up to study the relationship between the replacement rate of recycled coarse aggregate r_(1),the replacement rate of red brick powder-fly ash r_(2),the replacement rate of red brick powder-slag r_(3)and slump,cube compressive strength f_(cu),splitting tensile strength f_(ts),cylinder axial compressive strength f_(c),elastic modulus E_(c),Poisson′s ratioμof geopolymer concrete.The results show that with the increase of substitution rate r_(1),the slump decreases first and then increases,and the mechanical properties of concrete decrease gradually.When r_(1)≤50%,f_(cu)is greater than 40 MPa.With the increase of substitution rate r_(2),the slump decreases and the mechanical properties of concrete gradually increase.When r_(2)=20%,the strength increases from 10.68%to 14.52%.With the increase of substitution rate r_(3),the slump decreases.When r_(1)≤50%,the mechanical properties first increase and then decrease.When r_(3)=10%,the strength increases from 5.39%to 9.99%.When r_(1)is large,r_(3)has an adverse effect on mechanical properties.