In-depth insight into the cementitious synergistic effect of steel slag and red mud on the properties of composite cementitious materials

Hao, Xiansheng; Liu, Xiaoming; Zhang, Zengqi; Zhang, Wei; Lü, Yang; Wang, Yaguang; Yang, Tongyuan

doi:10.1016/j.jobe.2022.104449

Cited by 22 publications

(15 citation statements)

References 44 publications

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“…absorption peak observed here was related to the CO3 2− ion vibrations of cal carbonation of the unprocessed RS and C-S-H [36] during the hardening of t [43]. The asymmetric stretching vibration of Si-O-T (T = Al or Si) was linked tinctive absorption peak at 995 cm −1 [44,45]. This was equivalent to the C-(A)-S the hydration products.…”

Section: Ftir Analysismentioning

confidence: 65%

Preparation and Micromechanics of Red Sandstone–Phosphogypsum–Cement Composite Cementitious Materials

Kong,

Zhou,

Guo

et al. 2023

Materials

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Based on the physical and chemical properties of red sandstone (RS), RS is used to produce composite cementitious materials. The flowability, mechanical strength, and micromechanics of a red sandstone–cement binary cementitious material (RS-OPC) were investigated as functions of the amount of RS replacing the cement (OPC). Additionally, the feasibility of producing red sandstone–phosphogypsum–cement composite materials (RS-PG-OPC) using the phosphogypsum (PG)- enhanced volcanic ash activity of RS was investigated. The products of hydration and microstructures of RS-OPC and RS-PG-OPC were analyzed by XRD, FTIR, TG-DTG, and SEM. RS enhanced the flowability of RS-OPC relative to the unmodified cement slurry but lowered its mechanical strength, according to the experiments. When the quantity of OPC replaced was greater than 25%, the compressive strength after 28 days was substantially reduced, with a maximum reduction of 78.8% (RS-60). The microscopic mechanism of RS-OPC suggested that the active SiO2 in the RS can react with Ca(OH)2 to produce C-S-H but can only utilize small quantities of Ca(OH)2, confirming the low volcanic ash activity of RS. RS was responsible for dilution and filling. The incorporation of 5% PG into RS-PG-OPC slowed the hydration process compared with RS-OPC without PG but also increased the flowability and aided in the later development of the mechanical strength. This was primarily because the addition of PG provided the system with sufficient Ca2+ and SO42− to react with [Al(OH)6]3− to form ettringite (AFt), therefore accelerating the dissolution of Al3+ in RS to generate more AFt and C-(A)-S-H gels. To some extent, this excites the volcanic ash of RS. Therefore, if there is an abundance of waste RS in the region and a lack of other auxiliary cementitious materials, a sufficient quantity of PG and a finely powdered waste RS component can be used to replace cementitious materials prepared with OPC to reduce the mining of raw OPC materials.

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Section: Ftir Analysismentioning

confidence: 65%

Preparation and Micromechanics of Red Sandstone–Phosphogypsum–Cement Composite Cementitious Materials

Kong,

Zhou,

Guo

et al. 2023

Materials

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“…It can be seen that the peak intensity of C-S-H in the XRD pattern of the sample CFSR and CFR are larger than those of the sample FSR. This is because the incorporation of Ca(OH) 2 increases the content of Ca(OH) 2 , OH − , and Ca 2+ in the system, and the pH of the system becomes larger, prompting the precursor to dissolve more silicon–aluminum substances, and these silicon–aluminum substances will react with Ca(OH) 2 to form C(N)-A-S-H and C-S-H gels [ 27 ]. Meanwhile, the peak intensity of C-S-H increased after the incorporation of SS, indicating that the addition of SS can promote the formation of more gels in the matrix, which also explains why the compressive strength of the sample CFSR is much larger than that of the sample CFR.…”

Section: Resultsmentioning

confidence: 99%

“…Combined with the other pore structure parameters of the two samples and the previous analysis results, a possible explanation is that on the one hand, the sample CFSR generates more hydration products than the sample CFR to fill the harmful pores in the matrix, and on the other hand, the incorporation of SS has different particle size gradations with the original FA and RM particles. The close packing between these particles and hydration products can also reduce the proportion of harmful pores in the matrix [ 27 ].…”

Section: Resultsmentioning

confidence: 99%

In-Depth Insight into the Effects of Steel Slag and Calcium Hydroxide on the Properties of a Fly Ash–Red Mud Geopolymer

Wang,

Chen,

Ming

et al. 2024

Materials

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The low mechanical strength of a low-calcium fly ash (FA)–red mud (RM) geopolymer severely limits its application. Steel slag (SS) and Ca(OH)2 can provide calcium and alkali for the hydration process of a low-calcium FA-based geopolymer. In this study, SS was used to replace part of the RM, and Ca(OH)2 was introduced. The effects of SS and Ca(OH)2 on the properties of the FA-RM geopolymer were investigated. The experimental results show that SS promoted the matrix to generate more C(N)-A-S-H and C-S-H gels and optimized the pore structure, thereby improving the mechanical properties of the FA-based geopolymer. The addition of 4 wt.% Ca(OH)2 increased the hydration products of the FA-based geopolymer, the microstructure was denser, and the mechanical properties were significantly improved. The 28 d compressive strength of the FA-based ternary composite geopolymer prepared by replacing part of the RM with SS and adding Ca(OH)2 reached 30.6 MPa, which provided an experimental basis for the resource utilization of various bulk solid wastes.

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“…The absorption bands at 1640 cm −1 and 1416 cm −1 are attributed to H-O-H in free water and Si-OH in the C-S-H gel, respectively [ 28 ]. The band at 985 cm −1 and 876 cm −1 corresponds to Si-O-T (T = Si/Al) within the C/N-A-S-H gel [ 19 , 29 ] and CO 3 2− in CaCO 3 [ 30 ]. It can also be seen that the intensity of bonds at 3642 and 1640 cm −1 declined with reaction time.…”

Section: Resultsmentioning

confidence: 99%

Effect of Phosphorus Slag Admixture on the Properties and Hydration Mechanism of Circulating Fluidized Bed Fly Ash-Based Multi-Solid Waste Cementitious Material

et al. 2022

Self Cite

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This research aims to reveal the effect of phosphorus slag (PS) admixtures on the properties and hydration mechanism of circulating fluidized bed fly ash (CFA)-based multi-solid waste cementitious material (CWM). The results indicate that PS as an admixture is more helpful for improving the performance of CWM systems compared with blast furnace slag with a high specific surface area (HBFS) and gasification slag (GS). In this work, CWM2 is prepared with 30 wt.% CFA, 10 wt.% red mud (RM), 20 wt.% blast furnace slag (BFS), 10 wt.% PS, and 30 wt.% cement clinker (CC). The compressive strength and expansion value of CWM2 are the optimal (51.15 MPa and 0.70 mm) when the mass ratio of (Ca + Na)/(Si +Al) is 0.84, which can meet the requirements of 42.5 fly ash Portland cement. In addition, the polymerization degree of CWM2-28 days is the optimum (51.57%) because [PO4] and [SiO4] combine to improve its polymerization structure. The main hydration products are C-S-H gel, C/N-A-S-H gel, and ettringite in CWM, which are conducive to improve the compactness of the micromorphology. In addition, the consolidation of Na, As, Cd, and Hg is promoted in CWM2 by physical encapsulation and charge balance, which meet the drinking water requirements of the World Health Organization (WHO). Therefore, this work provides a new idea for the application of PS as an admixture in CFA-based multi-solid waste cementitious material.

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In-depth insight into the cementitious synergistic effect of steel slag and red mud on the properties of composite cementitious materials

Cited by 22 publications

References 44 publications

Preparation and Micromechanics of Red Sandstone–Phosphogypsum–Cement Composite Cementitious Materials

Preparation and Micromechanics of Red Sandstone–Phosphogypsum–Cement Composite Cementitious Materials

In-Depth Insight into the Effects of Steel Slag and Calcium Hydroxide on the Properties of a Fly Ash–Red Mud Geopolymer

Effect of Phosphorus Slag Admixture on the Properties and Hydration Mechanism of Circulating Fluidized Bed Fly Ash-Based Multi-Solid Waste Cementitious Material

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