凹凸棒土对3D打印水泥基材料工作性能及抗压强度的影响

Effect of Attapulgite Clay on Working Performance and Compressive Strength of 3D Printed Cementitious Materials

高掺量粉煤灰应用于3D打印混凝土中存在建造性和抗压强度等性能降低的问题,为了改善这一问题,本文将凹凸棒土(ATP)作为掺合料,研究了凹凸棒土掺量(0%、1%、2%和3%,质量分数)对高掺量粉煤灰3D打印水泥基材料工作性能及抗压强度的影响。结果表明,ATP吸附了浆体中大量水分,且填充了较大水泥颗粒的空隙,使浆体流动度降低,强度和屈服应力增大。当ATP掺量为1%~3%时,样品的挤出性和建造性良好。随着ATP掺量增加,养护7和70 d的打印试块在X、Y和Z三个方向的抗压强度均高于对照组。养护7 d时,ATP掺量为3%的试块在Z方向抗压强度最大,为14.0 MPa;养护至70 d时,ATP掺量为2%的试块在Y方向的抗压强度最大,达到了24.1 MPa。

The application of high-volume fly ash in 3D printing concrete has the problem of reduced performance such as buildability and compressive strength.In order to improve this problem,attapulgite was used as an admixture in this paper.The effect of attapulgite clay(ATP)content(0%,1%,2%and 3%,mass fraction)on the working performance and compressive strength of high-volume fly ash 3D printing cement-based materials was studied.The results show that ATP adsorbs a large amount of water in slurry and fills the voids of larger cement particles,which reduces the fluidity of slurry and increases the strength and yield stress of slurry.When the content of ATP is 1%~3%,the extrudability and buildability of sample are good.With the increase of ATP content,the compressive strength of the printed test block curing for 7 and 70 d in X,Y and Z directions is higher than that of control group.When the curing time is 7 d,the compressive strength of sample with 3%ATP in Z direction is the largest,which is 14.0 MPa.When the curing time is 70 d,the compressive strength of sample with 2%ATP in Y direction is the largest,reaching 24.1 MPa.