Calcium nitrate as a modifier agent for metakaolin-based geopolymer mortar

IF 7.4 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Construction and Building Materials Pub Date : 2024-11-22 DOI:10.1016/j.conbuildmat.2024.139199

Alaa M. Rashad , Ghada M.F. Essa , W.M. Morsi , E.A. Fahmy

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引用次数: 0

Abstract

Calcium nitrate, that is a calcium source, is generally used as an accelerating agent, antifreezing admixture, and corrosion inhibitor for Portland cement systems. Metakaolin, which is regularly used as a precursor in the production of geopolymers, lacks calcium. This can cause inefficiency of the geopolymerization process and alter the properties of the cementitious product. To overcome this problem, the potential benefits of adding calcium nitrate as an alternative calcium source for the metakaolin geopolymer mortar were investigated. Different ratios of calcium nitrate, ranging from 0.5 % to 10 %, were added into metakaolin geopolymer mortar. Different tests were conducted to know the effect of calcium nitrate on some properties of metakaolin geopolymer specimens, which were cured in either air or water. Advanced analysis methods were leveraged to unlock deeper meaning from the findings. The results indicated that adding calcium nitrate led to increased flowability and shortened setting time. The addition of 0.5–7 % calcium nitrate increased mechanical strength but reduced transport properties, whilst the addition of 10 % calcium nitrate led to adverse effects. The addition of 0.5–7 % calcium nitrate can mitigate the strength deterioration rate resulting from water curing and decrease drying shrinkage. The incorporation of appropriate ratios of calcium nitrate can form calcium silicate hydrate gel and densify the microstructure.

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来源期刊

Construction and Building Materials 工程技术-材料科学：综合

CiteScore

13.80

自引率

21.60%

发文量

3632

审稿时长

82 days

期刊介绍： Construction and Building Materials offers an international platform for sharing innovative and original research and development in the realm of construction and building materials, along with their practical applications in new projects and repair practices. The journal publishes a diverse array of pioneering research and application papers, detailing laboratory investigations and, to a limited extent, numerical analyses or reports on full-scale projects. Multi-part papers are discouraged. Additionally, Construction and Building Materials features comprehensive case studies and insightful review articles that contribute to new insights in the field. Our focus is on papers related to construction materials, excluding those on structural engineering, geotechnics, and unbound highway layers. Covered materials and technologies encompass cement, concrete reinforcement, bricks and mortars, additives, corrosion technology, ceramics, timber, steel, polymers, glass fibers, recycled materials, bamboo, rammed earth, non-conventional building materials, bituminous materials, and applications in railway materials.