摘要
为了研究纳米SiO_(2)对滨海水泥土短龄期的力学改性效果,开展了纳米SiO_(2)掺量(与水泥质量比)分别为0%、1.5%、3.0%、4.5%和6.0%的水泥土无侧限抗压试验、劈裂抗拉试验、pH试验、SEM试验。力学试验表明,纳米SiO_(2)能够提高水泥土的无侧限抗压强度、劈裂抗拉强度和弹性模量,但加剧了水泥土的脆性;纳米SiO_(2)改性水泥土的抗压强度大约为抗拉强度的10倍;pH测试表明,纳米SiO_(2)能够改善水泥土的碱性环境。SEM微观测试发现,水泥土颗粒形态、孔隙特征变化规律与强度发展规律关系紧密,随着纳米SiO_(2)掺量的增加,土颗粒形态分布由松散变为聚集,并伴随孔隙的减少。综上发现,纳米SiO_(2)掺量为4.5%时,强度改善效果最佳,微观孔隙最少,4.5%为最优掺量。最后,建立了纳米SiO_(2)改性水泥土力学强度与微观孔隙率之间的二次多项式模型。
In order to study the mechanical modification effect of nano-SiO_(2)on coastal cement soil at short age,unconfined compression test,splitting tensile test,pH test and SEM test of cement soil with nano-SiO_(2)content(mass ratio to cement)of 0%,1.5%,3.0%,4.5%and 6.0%were carried out.Mechanical tests show that nano-SiO_(2)can improve the unconfined compressive strength,splitting tensile strength and elastic modulus of cement soil,but aggravate its brittleness;the compressive strength of nano-SiO_(2)modified soil is about 10 times of its tensile strength.The pH test shows that nano-SiO_(2)can improve the alkaline environment of cement soil.SEM micro test shows that the change law of cement soil particle morphology and pore characteristics is closely related to the strength development law.With the increase of nano-SiO_(2)content,the distribution of soil particle morphology changes from loose to aggregate,and the pores decrease.In conclusion,when the nano-SiO_(2)content is 4.5%,the strength improvement effect is the best,the micro pores are the least,and 4.5%is the best content.Finally,the quadratic polynomial model between mechanical strength and micro porosity of nano-SiO_(2)modified cement soil is established.
作者
王伟
刘静静
李娜
马露
WANG Wei;LIU Jingjing;LI Na;MA Lu(School of Civil Engineering,Shaoxing University,Shaoxing 312000,China;Key Laboratory of Rock Mechanics and Geohazards of Zhejiang Province,Shaoxing 312000,China;Geotechnical Engineering Research Institute,Hohai University,Nanjing 210009,China)
出处
《复合材料学报》
EI
CAS
CSCD
北大核心
2022年第4期1701-1714,共14页
Acta Materiae Compositae Sinica
基金
国家自然科学基金(41772311)。
