Abstract Sulphate-induced heaving in soils is a common problem caused mostly by the use of calcium-based binders in the stabilisation of sulphate-bearing soils. Sulphate-induced heaving is attributed to precipitation and growth of ettringite minerals in a high alkaline environment. A sustainable means of reducing sulphate-induced heaving by the addition of an additive called “RoadCem” (RC) to soils stabilised by calcium-based cementitious products has not been studied. RoadCem (RC) is an additive that is manufactured based on nanotechnology and comprises synthetic zeolite, alkaline metals and some complex activators as some of its constituents. This research is therefore concerned with the performance of a sulphate-bearing soil stabilised by partially substituting cement (CEM I) with ground granulated blast furnace slag (GGBS) and incorporation of marginal quantities of RC. Laboratory studies including oedometer free swelling testing, unconfined compressive tests and microstructural analyses of the phases of hydration in the stabilised soils were carried out. Results indicated a reduction in heave by about 67% when 1% of RC was included in the cementitious mix with 50% of the CEM I replaced by a combination of GGBS and RC. The use of RC in the stabilised soil was even more promising than that in which only GGBS was utilised to replace half of the CEM I proportion in the stabilised soil with the result indicating almost a 30% difference in heave reduction. Results also indicated an increase in the unsoaked strength of stabilised soil with RC inclusion compared to the stabilised mix without RC. Scanning electron micrograph studies revealed almost a complete elimination of heave-causing ettringite minerals under a 28-day hydration phase of the stabilised soil when using RC.

中文翻译：

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将基于纳米技术的产品加入水泥粘合剂中，以可持续地减轻硫酸盐引起的稳定土壤的隆起

摘要 土壤中硫酸盐引起的隆起是一个常见的问题，主要是由于使用钙基粘合剂稳定含硫酸盐土壤而引起的。硫酸盐诱发的隆起归因于钙矾石矿物在高碱性环境中的沉淀和生长。尚未研究通过向由钙基水泥产品稳定的土壤中添加称为“RoadCem”(RC) 的添加剂来减少硫酸盐引起的隆起的可持续方法。RoadCem (RC) 是一种基于纳米技术制造的添加剂，其成分包括合成沸石、碱金属和一些复杂的活化剂。因此，本研究关注的是通过用磨碎的高炉矿渣 (GGBS) 部分替代水泥 (CEM I) 并加入少量 RC 来稳定的含硫酸盐土壤的性能。进行了实验室研究，包括固结仪自由膨胀试验、无侧限压缩试验和稳定土壤中水化阶段的微观结构分析。结果表明，当 1% 的 RC 包含在水泥混合物中，50% 的 CEM I 被 GGBS 和 RC 的组合代替时，垂荡降低了约 67%。在稳定土壤中使用 RC 比在稳定土壤中仅使用 GGBS 代替一半的 CEM I 比例更有希望，结果表明在降低升沉方面几乎有 30% 的差异。结果还表明，与不含 RC 的稳定混合物相比，含有 RC 的稳定土壤的未浸泡强度有所增加。扫描电子显微照片研究表明，当使用 RC 时，在稳定土壤的 28 天水化阶段几乎完全消除了引起隆起的钙矾石矿物。