多孔生态混凝土强度与孔隙率的试验研究

为探索适合多孔生态混凝土的配合比设计方法,采用正交试验法对多孔生态混凝土的抗压强度和孔隙率及主要影响因素进行了试验研究.结果显示,试样的实测孔隙率13.8%～31.5%,平均值为25.24%,与目标值相近;实测抗压强度为3.49～18.2 MPa,平均值9.75 MPa,仅为理论值的9.21%～48.02%.孔隙率超过20%时,强度随孔隙率的增加快速下降.在孔隙率为31.5%时,强度仅3.49 MPa,与目标强度相差较大.试验结果也表明,多孔生态混凝土的强度和孔隙率除受水灰比的影响外,灰集比是主要影响因素.灰集比越大,抗压强度越高,但孔隙率也随之减小,说明现有混凝土的强度理论不适合多孔生态混凝土的配合比设计.通过回归分析建立的孔隙率和混凝土强度设计公式(4)和(5),综合考虑了水灰比、灰集比和外加剂的影响,可联立用于多孔生态混凝土的配合比设计.

Experimental study on strength and porosity ratio of porous ecological concrete

In order to explore mix design method of porous ecological concrete,the paper analyzed the strength and porosity of porous ecological concrete based on orthogonal test method.The result showed that the observed porosity was on the rage of 13.8% to 31.5%,the average was about 25.24%,which was near to the target value.However,the observed compression strength was about 3.49 to 18.2 MPa,the average was about 9.75 MPa,which was just the theoretical values 9.21%to 48.02%.According to the test,when the porosity was over 20 percent,strength would be rapidly decreased.When the porosity was 31.5%,the strength was just 3.49 MPa,which was far lower than the target value.The test also showed that the strength and porosity were also affected by ash set ratio.The bigger the ash set ratio,the higher compression strength,but the porosity would low.This could explain that the existed strength theory was not fit to the mix design of porous ecological concrete.According to the experimental results,the empirical formula(4)and formula(5) about compressive strength and porosity design is established through regression analysis.The empirical formula can guide mix design of porous ecological concrete.