Effect of steel slag powder and stone powder by-product from manufactured sand on the mechanical properties and microstructure of cementitious materials

• Published in: Journal of cleaner production 2024-05, Vol.452, p.142128, Article 142128
• Main Authors: Tian, Erbu, Ren, Weigang, Zhuang, Yizhou, Zeng, Wuhua
• Format: Article
• Language: English
• Subjects: Cementitious materials; Mechanical properties; Microstructure; Steel slag powder; Stone powder
• ISSN: 0959-6526; 1879-1786
• DOI: 10.1016/j.jclepro.2024.142128

Incorporating steel slag (SS) and stone powder (SP) as supplementary cementitious materials (SCMs) in cement and concrete products is an effective approach to promoting environmental protection. Recently, the effect of using steel slag alone is not satisfactory and the performance of blended cementitious materials is expected to improve after compounding with other admixtures. In this study, steel slag powder (SSP) and SP by-products from manufactured sand were employed with a total dose of less than 30% as a replacement for cement. The results revealed that the blended cementitious materials exhibited excellent mechanical strength and pore structure with the synergistic effect of SSP and SP. Compared to SSP or SP doping alone, the activity index of the composite 25% SSP and 5% SP was higher. SSP offers a considerable retardation effect on cement, while SP has little effect. Conversely, the effect of steel slag on mortar fluidity is neglected and SP decreases the fluidity. When 5% SSP is combined with 5% SP, the initial and final setting times of cement are increased by 39% and 25%, respectively. The reduction in mortar fluidity amounted to an insignificant reduction of only 0.7%, and the strength of the mortar at 28 d and 180 d was only lost by 7% and 5%, respectively. The coaction of 15% SSP and 15% SP was observed to promote the wollastonite generation, enhance the crystallization degree of xonotlite phases, decrease the microcrack widths, and optimize the pore structure of the blended cementitious materials. •The performance of SSP and SP on cementitious materials was investigated.•SSP and SP had a synergistic effect on the properties of cementitious materials.•Wollastonite was formed under the simultaneous action of SSP and SP.•Combining suitable SSP and SP was favorable for the matrix pore structure.•A rare hydrated calcium silicate mineral was formed in the case of mono-doped SP.