赤泥-秸秆基轻质砂浆的制备及其性能表征

Preparation and Characterization of Red Mud-Straw Based Lightweight Mortar

以拜耳法赤泥、矿渣微粉、水泥(P.O 42.5)和秸秆为原料,制备赤泥-秸秆轻质砂浆试样,并通过X射线衍射和扫描电镜等研究秸秆掺量对试样性能的影响。结果表明:对于由质量分数50%的赤泥和质量分数为50%的水泥和矿渣混合物制备而成的赤泥胶凝材料净浆硬化试样,水泥、矿渣混合物中随着水泥含量减少,试样各龄期抗压强度先提高后降低,且在水泥、矿渣质量比为1∶3时,试样的抗压强度最高,为8.05 MPa;在赤泥-秸秆轻质砂浆中加入体积分数为10%的秸秆,试样的抗压强度降低,由无秸秆试样的10.45 MPa降低至7.25 MPa,但随秸秆掺量的继续增加,试样抗压强度降低幅度减小,抗折强度却随之增大,在秸秆掺量体积分数为50%时达1.9 MPa;随着秸秆掺量的增加,试样容重降低幅度不大,但导热系数降低显著,由无秸秆试样的0.63W/(mK)降低至体积分数50%秸秆试样的0.40 W/(mK)。

The red mud-straw lightweight mortar specimens were prepared,which were based on raw materials of the Bayer red mud,slag powder,cement(P.O 42.5),as well as straw.The effect of straw content on the properties of specimens were characterized by X ray diffraction and scanning electron microscope.The results show that for cement paste hardening specimens prepared with 50%mass fraction of red mud and 50%mass fraction of the mixture of cement and slag powder,with the decrease of cement content in the mixture of cement and slag,the compressive strength of hardening specimen of red mud cementitious material paste at different ages increases at first and then decreases,when the mass ratio of cement to slag is 1∶3,the compressive strength of the sample is the highest of 8.05 MPa.When straw with 10%volume fraction is added into red mud-straw lightweight mortar,the compressive strength of the specimens decrease from 10.45 MPa to 7.25 MPa.However,as the straw content continues to increase,the decrease range of compressive strength of the specimen decreases,while the flexural strength increases,and it reaches 1.9 MPa when the volume fraction of straw is 50%.With the increase of straw content,the specific weight of the specimen decreases slightly,but the thermal conductivity decreases significantly,from 0.63 W/(mK)of the specimen without straw powder to 0.40 W/(mK)of the specimen of straw with 50%volume fraction.