工业废料胶结剂加固土与普遍水泥加固土的对比试验研究

工业废料胶结剂是指一种利用工业废料加工而成的用于深层搅拌的新型土体胶结剂,本文主要讨论并对比了工业废料胶结剂加固土与４２５号普通硅酸盐水泥土的无侧限抗压强度试验,以验证工业废料胶结剂代替普通水泥的可行性。同时,对无侧限抗压强度的影响因素进行了分析,并给出了相应的关系表达式。     

工业废料胶结剂加固土与普通水泥加固土的对比试验研究

工业废料胶结剂是指一种利用工业废料加工而成的用于深层搅拌桩的新型土体胶结剂.本文主要讨论并对比了工业废料胶结剂加固土与425号普通硅酸盐水泥土的无侧限抗压强度试验,以验证工业废料胶结剂代替普通水泥的可行性.同时,对无侧限抗压强度的影响因素进行了分析,并给出了相应的关系表达式.     

深层搅拌桩新型胶结材料的试验研究

介绍了一种利用工业废料加工的深层搅拌桩新型土体胶结剂,并将工业废料加固土的无侧限抗压强度、渗透系数、压缩模量、三轴抗剪强度的试验结果以及静载荷试验结果与水泥加固土进行了对比分析,结果发现：工业废料加固土与水泥加固土具有同样的工程性质。另外,还给出了工业废料加固土无侧限抗压强度随时间增长的关系表达式,他工业放心料胶结料加固软基的机理。     

不同土性对加固土加固性能的影响

本文通过试验讨论了上海地区三种典型的土质对加固土的不同影响.从重度测试和无侧限抗压强度试验着手,总结出不同土性下加固土重度和无侧限抗压强度的变化规律,并且为采用搅拌桩及类似方法的复合地基提供了更可靠的理论依据.文中还对比了工业废料加固土和425#普硅水泥加固土受土性影响的差异.     

粉煤灰炉渣加固土的室内无侧限抗压强度试验研究(英文)

给出了用粉煤灰、炉渣等工业废料加固土的室内无侧限抗压强度试验结果,分析了加固土无侧限抗压强度与外加剂掺量、养护龄期之间的影响规律,得出了针对不同工业废料加固土所用外加剂的最佳掺量。     

不同土性对加固土加固性能带来的影响

本文通过试验讨论了上海地区三种典型的土质对加固土的不同影响。从重度试验和无侧限抗压强度试验着手,总结出不同土性下加固土 重度和无侧限抗压强度的变化规律,并且为采用搅拌桩及类似方法的复合地基提供了更可靠的理论依据。文中 还对比 了工业废料加固土和425^# 普硅水泥加固土受土性影响的差异。     

掺加工业废料加固土的试验研究

介绍了一种新型加固土。从水泥土固化机理出发,讨论并对比了掺加工业废料加固土与普通水泥土的无侧限抗压强度试验。     

水泥加固酸污染土无侧限强度特征

污染土是利用水泥固化处理后,土体的强度得到提高。针对该项技术,采用水泥固化法处理酸污染土,通过两种试验方案,对水泥加固酸污染土的无侧限抗压强度特性进行研究。试验所用酸污染土用浓硫酸配置人工制备而成,并考虑了不同水泥掺量、不同硫酸浓度和不同龄期对水泥加固酸污染土强度的影响。试验表明:水泥固化酸污染土的强度与水泥掺量和硫酸含量有密切关系,二者共同作用决定其强度的变化。在一定硫酸浓度(2~16g/kg)条件下,伴随硫酸含量的升高,水泥掺量较低时,无侧限抗压强度整体呈明显下降的趋势;水泥掺量较高时,无侧限抗压强度呈缓慢上升的趋势。随着水泥掺量提高,土样的无侧限抗压强度达到峰值时所对应的硫酸含量也逐渐变大。     

基于水灰比准则的水泥土无侧限抗压强度预测

现行规范对于水泥加固土无侧限抗压强度预测方法不明确,通过引用D.Abrams提出的混凝土水灰比理论,修正了水泥固化高含水率疏浚泥无侧限抗压强度预测方法,为减少室内试验量和缩短工期提供了依据。     

胶州湾地区水泥土的无侧限抗压强度试验研究

根据胶州湾地区不同地基土所做成的水泥土试样的无侧限抗压强度试验,得出本地区水泥土的特性。通过大量勘察资料和试验数据,得出了水泥淤泥土、水泥粘土和水泥砂土的不同破坏形式及无侧限抗压强度。     

Plasticity role in strength behavior of cement-phosphogypsum stabilized soils

Dredged soil and phosphogypsum are frequently regarded as wasted materials, which require further treatment to control their environmental impact. Hence, phosphogypsum is proposed as a binder to stabilize dredged soil, aiming at efficiently reducing and reusing these waste materials. In this study, the engineering properties of cement-phosphogypsum stabilized dredged soils were investigated through a series of unconfined compression tests, and the effects of plasticity index of original soils on the strength improvement were identified. Then, the microstructure test and mineralogical test were performed to understand the mechanism of physical role of original soils in strength improvement. The results revealed that the unconfined compressive strength significantly decreased with the increase in plasticity index at the same binder content. The essential factor for strength improvement was found to be the formation of cementitious materials identified as calcium silicate hydrate (CSH), calcium aluminate hydrate (CAH), and ettringite (Aft). The normalized integrated intensity of cementitious materials (CSH + CAH + Aft) by pore volume decreased with the increase in plasticity index. Consequently, the density of cementitious materials filling the soil pores controlled the effectiveness of strength improvement. More cementitious materials per pore volume were observed for the original soils with lower values of plasticity index. That is, the higher strength of stabilized soils with lower values of plasticity index was attributed to a packed structure forming by integrated fabric through denser cementitious components. It can be anticipated from the above findings that the effectiveness of stabilization treatment will significantly reduce with the increase in plasticity of origin soil.     

大掺量磷石膏用于路基填料的性能试验研究

为探索磷石膏大掺量、规模化、资源化利用路径,分别以自制固化剂和水泥为胶凝材制备大掺量磷石膏路基填料,开展大掺量磷石膏混合料的击实试验、无侧限抗压强度试验及疏水改性试验,分析大掺量磷石膏与自制固化剂和水泥的适配性、击实特性、强度特性、耐水性能。结果表明,采用水泥或自制固化剂改性磷石膏击实曲线呈单峰变化趋势,且含水率偏低时对大掺量磷石膏混合料的干密度影响较小;相同配比时,固化剂体系大掺量磷石膏混合料7d无侧限抗压强度是水泥体系的1.5倍以上,磷尾砂与自制固化剂的适配性优于黏土,且配比为90%磷石膏+10%固化剂的大掺量磷石膏混合料7d无侧限抗压强度度达3.4MPa,经疏水改性后强度提升至4.2MPa,疏水剂与自制固化剂的复配较好地改善了磷石膏自身亲水特性,提升了其水稳性能。     

Role of Fly Ash on Strength and Microstructure Development in Blended Cement Stabilized Silty Clay

This paper presents the role of fly ash on strength and microstructure development in blended cement stabilized silty clay. Its strength was examined by unconfined compression test and its microstructure (fabric and cementation bond) by a scanning electron microscope (SEM), mercury intrusion porosimetry (MIP), and thermal gravity (TG) analysis. The flocculation of clay particles due to the cation exchange process is controlled by cement content, regardless of fly ash content. It increases dry unit weight of the stabilized clay with insignificant change in liquid limit. This results in irrelevant difference in optimum water content (OWC) for the unstabilized and the stabilized clay since OWC of low swelling silty clay is mainly controlled by liquid limit. It is found from the microstructural and the strength test results that the reactivity of fly ash (pozzolanic reaction) is minimal, which is different from concrete technology. This is possibly due to less amount of Ca(OH)₂ to be consumed. The role of fly ash in cement stabilization is to disperse the large clay-cement clusters into smaller clusters. Consequently, the reactive surfaces to be interacted with water increase, and hence the cementitious products (inter-cluster cementation bond). To conclude, the strength development in the blended cement stabilized clay is controlled by cementitious products due to combined effect: hydration and dispersion. Cementitious products due to hydration are governed by cement content, while cementitious products due to dispersion by fly ash content and fineness. Water content of 1.2OWC and 10% replacement ratio are regarded as the effective mixing condition for the stabilization, exhibiting the highest cementitious products.     

固废基胶凝材料在干旱地区公路基层中的路用性能研究

针对水泥稳定材料引起的基层开裂及缓凝时间短的问题,采用粉煤灰、矿渣粉、脱硫石膏、电石渣为主要原料,配制道路水稳层路用胶凝材料,代替缓凝硅酸盐水泥。结果表明,固废基胶凝材料凝结时间相较水泥延迟了2h,其7d和28d抗折、抗压强度均满足规范要求;固废基稳定混合料14d及28d无侧限抗压强度与水泥稳定混合料7d及28d基本相等,同时28d冻融循环残留强度与30次抗硫酸盐耐腐蚀系数均大于85%,高于水泥稳定材料;固废基稳定混合料90d时试验段贯通裂缝数量4～5条,小于水泥稳定混合料数量的1/7。     

上海水泥固化黏土的强度与硬度相关性研究

现场施工过程中,往往需要对水泥固化土的无侧限抗压强度进行快速检测。针对目前水泥固化黏土无侧限抗压强度检测中存在的操作不简便、试验时间长、测试费用高等缺点,提出通过水泥土硬度估计强度的方法,对现场水泥土强度进行快速检测。本文以上海地区黏性土为研究对象,对上海地区水泥固化黏土强度与硬度的相关性进行了试验研究;探讨了加固土的硬度与养护时间、水泥掺量以及强度与硬度之间的关系。试验结果表明:上海黏土水泥土强度和硬度呈正比相关,对数坐标下的强度和硬度有着形如lnq_u=ap+b的线性关系。养护初期,硬度增长速度大于水泥土强度增长速度。养护后期,强度增速大于硬度增速。     

水泥固化重金属铅污染土的强度特性研究

污染场地中开挖出来的污染土利用水泥固化处理（S/S法）后,其污染物质的淋滤特性和土体的强度得到改善,可用于场地的回填和堤坝的填筑等。针对该项技术,对水泥固化稳定后的重金属铅污染土的强度特性进行了研究。试验所用的铅污染土通过将硝酸铅溶液加入干土中人工制备而成,并考虑了不同铅离子含量和水泥掺量对水泥固化污染土强度特性的影响。试验结果表明：水泥固化污染土的无侧限抗压强度随着水泥掺量以及龄期的增长而提高;与常规水泥土（不含重金属污染物）强度相比,污染土中铅离子含量较低时,强度略有提高,铅离子含量较高时,强度显著降低;不同铅含量水泥土试样的应力应变关系均表现为强度越高,破坏应变越小;试样28 d龄期的变形模量与强度呈较好的线性对应关系。     

夯实水泥土桩桩体强度特性的探讨

本文通过试块的无侧限抗压强度试验研究,并结合新版行业标准《建筑地基处理技术规范》(JGJ79-2002)和同行的研究成果,对影响夯实水泥土桩桩体强度的主要因素进行探讨。