首页|矿渣-白泥固化黄土的力学性能与微观机理

矿渣-白泥固化黄土的力学性能与微观机理

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为探究矿渣与白泥固废材料应用于黄土路基加固的可行性,并解决传统石灰固化黄土强度较低以及生产污染大的问题,制备了矿渣-白泥胶凝材料,随后使用不同掺量(0%、5%、10%、15%)的矿渣-白泥胶凝材料对黄土进行固化,结合基本物理化学性质,探究了固化黄土的无侧限抗压强度以及耐久性(干湿和冻融)的变化规律,并通过XRD、TG/DTG和SEM揭示了其微观机理.试验结果表明:矿渣-白泥胶凝材料中矿渣占比越高强度增长潜力越大,但矿渣占比超过70%时,会导致试样无法成型;适当增加其中的白泥占比,可以提高pH值以及早期强度,综合成本来看其最佳配比为60∶40;未浸水条件下,10%掺量时矿渣-白泥固化黄土 28 d无侧限抗压强度为4.9 MPa,相比于石灰固化黄土提高2.2倍,水稳定系数提高0.45倍,满足路基填料强度要求;矿渣-白泥胶凝材料可以显著提高黄土的耐久性,10%与15%掺量时固化黄土经14次冻融后强度和质量变化均小于2%,固化黄土的强度随干湿循环次数先增加后降低,并且12次干湿循环后强度均高于28 d强度.微观测试表明:白泥能促进矿渣的水化作用,矿渣-白泥胶凝材料的主要水化产物为CSH等凝胶,CSH凝胶的胶结作用是固化黄土强度和耐久性提升的主要来源,而填充效果起到次要作用.
Mechanical Properties and Microscopic Mechanism of Slag-white Mud Solidified Loess
To explore the feasibility of slag-white mud solid waste material for loess subgrade reinforcement and to solve the problems of low strength and high pollution in the production of lime loess,this study prepared a slag-white mud cementing material and used different dosages(0%,5%,10%,and 15%)of slag-white mud cementing material to solidify the loess.The unconfined compressive strength and durability of the solidified loess were investigated based on its physical and chemical properties,and the microscopic mechanism was revealed through X-ray diffraction,thermogravimetry/differential thermogravimetry,and scanning electron microscopy.Results show that the higher the proportion of slag in the slag-white mud cementing material,the greater is the strength growth potential.However,when the slag proportion is greater than 70%,the sample cannot be formed.An appropriate increase in the proportion of white mud can improve the pH and early strength.The best slag is that with a white mud ratio of 60∶40 under the consideration of cost and strength.Under a no-soaking condition,the unconfined compressive strength of slag-white mud solidified loess at 28 d is 4.9 MPa at a 10%dosage,which is 2.2 times higher than that of lime solidified loess,and the water stability coefficient is 0.45 times higher than that of the lime solidified loess.The strength and quality of the solidified loess with 10%and 15%dosages change by less than 2%after 14 freeze-thaw cycles.The strength of the solidified loess first increases and then decreases with the number of dry-wet cycles,and the strength of the solidified loess after 12 dry-wet cycles is higher than that after 28 d.Microscopic experiments show that white mud promotes the slag hydration reaction.The main hydration products of slag-white mud cementing materials are CSH-type gels.The cementation of the CSH gel is the main source of strength and durability improvement,where the filling effect plays a secondary role.

subgrade engineeringsolidified loessmechanical strength testingslag-white muddurability

薛志佳、罗江、晏长根、张营、张英立、贾小龙

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长安大学公路学院,陕西西安 710064

成都市市政工程设计研究院有限公司,四川成都 610023

宁夏交通建设股份有限公司,宁夏银川 750002

路基工程 固化黄土 力学强度测试 矿渣-白泥 耐久性

国家自然科学基金青年基金项目宁夏回族自治区重点研发计划项目陕西省高校科协青年人才托举计划项目中国博士后科学基金项目陕西省自然科学基础研究计划项目中央高校基本科研业务费专项资金项目

419022802022BFE02006202104222022M7104862023-JC-QN-0445300102212101

2024

中国公路学报
中国公路学会

中国公路学报

CSTPCD北大核心
影响因子:1.607
ISSN:1001-7372
年,卷(期):2024.37(6)
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