锂渣和钢渣对水泥浆体力学性能与微观结构的影响

Effects of Lithium Slag and Steel Slag on Mechanical Properties and Microstructure of Cement Paste

利用锂渣粉和钢渣粉替代部分P·O42.5水泥制备了复合水泥净浆试样。通过SEM、XRD、FT-IR等测试方法分析了二者对试样的影响及作用机制。结果表明,锂渣替代部分水泥会降低浆体的流动性,钢渣替代部分水泥有利于提高浆体流动性。锂渣具有促凝效果,而钢渣在浆体中可发挥缓凝作用。锂渣、钢渣复合掺入时可调控浆体的流动性和凝结时间。锂渣对浆体力学性能的提高相比钢渣具有更明显的优势,当水胶比为0.4时,掺入20%(质量分数)锂渣的试样28 d抗压强度可达62.3 MPa,相比空白样可提高23%左右。SEM结果显示掺20%锂渣可使试样28 d微观结构更致密。XRD结果显示试样的水化产物主要为C-S-H凝胶和Ca(OH)_(2)。FT-IR结果显示Si—O键峰位发生了一定的红移,H—O—H键发生了蓝移。

Lithium slag(LS)powder and steel slag(SS)powder were used to partly replace the P·O 42.5 cement(PC)to prepare composite cement pastes.SEM,XRD and FT-IR were used to analyze the effects and mechanism of the two slags on samples.The results show that the replacement of part of cement with LS reduces the fluidity of paste,while the replacement of part of cement with SS is beneficial to improve the fluidity.LS promotes coagulation,while SS slows coagulation in paste.The fluidity and setting time of pastes are controlled by the combined effects of LS and SS.LS has more obvious advantages than SS in improving the mechanical properties of paste.When the water-binder ratio is 0.4,the compressive strength at 28 d of the sample mixed with 20%(mass fraction)LS reaches more than 62.3 MPa,which is about 23% higher than that of control sample.SEM results show that the microstructure of paste with 20% LS is denser than that of control sample at 28 d.XRD results show that the hydration products of the composite pastes are mainly C-S-H gel and calcium hydroxide.FT-IR results show that the peak position of Si—O bond has a red shift,and the H—O—H bond has a blue shift.