Cementitious mortars containing pozzolana under elevated temperatures

Toufigh, Vahab; Pachideh, Ghasem

doi:10.1002/suco.202100567

Cited by 12 publications

(4 citation statements)

References 32 publications

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“…The hydration reaction between fine aggregates and cementitious materials was inhibited by the high content of residual carbon in the CGCS, which hindered the growth and connection of hydration products and weakened the mechanical properties of mixtures. With the increase in CGCS replacement, the agglomeration phenomenon of FA became increasingly obvious ( Figure 9 ), thereby affecting the secondary hydration and the strength of concrete [ 50 , 51 ].…”

Section: Resultsmentioning

confidence: 99%

Mechanical Properties of Ultra-High Performance Concrete with Coal Gasification Coarse Slag as River Sand Replacement

Zhu¹,

Lian

Zhai

et al. 2022

Materials

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Coal gasification coarse slag (CGCS) is a by-product of coal gasification. Despite its abundance, CGCS is mostly used in boiler blending, stacking, and landfill. Large-scale industrial applications of CGCS can be environment-friendly and cost saving. In this study, the application of CGCS as a substitute for river sand (RS) with different replacement ratios in ultra-high performance concrete (UHPC) was investigated. The effects of CGCS replacement ratios on the fluidity and mechanical properties of specimens were examined, and the effect mechanisms were explored on the basis of hydration products and the multi-scale (millimetre-scale and micrometre-scale) microstructure analysis obtained through X-ray diffraction (XRD), scanning electron microscopy, and X-ray energy-dispersive spectroscopy. With an increase in the CGCS replacement ratio, the water–binder ratio (w/b), flexural strength, and compressive strength decreased. Specimens containing CGCS of ≤25% can satisfy the strength requirement of non-structural UHPC, with flexure strength of 29 MPa and compressive strength of 111 MPa at day 28. According to the XRD results and multi-scale microstructure analysis, amorphous glass beads in CGCS positively influenced ettringite generation due to the pozzolanic activity. Porous carbon particles in CGCS showed strong interfacial bonding with cement slurry due to internal hydration; this bonding was conducive to improving the mechanical strength. However, CGCS hindered hydration in the later curing stage, leading to an increase in the unreacted cement and agglomeration of fly ash; in addition, at a CGCS replacement ratio of up to 50%, an apparent interfacial transition zone structure was observed, which was the main contributor to mechanical strength deterioration.

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Section: Resultsmentioning

confidence: 99%

Mechanical Properties of Ultra-High Performance Concrete with Coal Gasification Coarse Slag as River Sand Replacement

Zhu¹,

Lian

Zhai

et al. 2022

Materials

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“…A large number of industrial wastes are used in the ECC preparation process to replace some or all of the cement, such as fly ash, slag, lithium slag and red-mud slag [ 27 , 28 , 29 , 30 , 31 ], and the energy consumption of the material-production process is greatly reduced, which conforms to the goal of achieving environmental sustainability [ 32 ]. Aggregates are an important component of the ECCs, which account for a large volume proportion and significantly affect the workability, strength, elastic modulus, ductility and other properties of the ECCs.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Toughness of Engineered Cementitious Composites with Desert Sand

Lv¹,

Han

Ge³

et al. 2023

Materials

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In this paper, engineered cementitious composites (ECCs) were prepared with desert sand instead of ordinary sand, and the toughness properties of the ECCs were studied. The particle size of the desert sand was 0.075–0.3 mm, which is defined as ultrafine sand. The ordinary sand was sieved into one control group with a size of 0.075–0.3 mm and three other reference groups. Together with the desert sand group, a total of five groups of ECC specimens were created. Through a uniaxial tensile test, three-point bending test and single-seam tensile test on the ECC specimens, the influence of aggregate particle size and sand type on the ECC tensile strength, deformation capacity, initial crack strength, cement-matrix-fracture toughness, multiple cracking characteristics and strain-hardening properties were studied. The experimental results show that the 28d tensile strain of the four groups of the ordinary sand specimens was 8.13%, 4.37%, 4.51% and 4.23%, respectively, which exceeded 2% and satisfied the requirements for the minimum strain of the ECCs. It is easier to achieve the ECC strain hardening with sand with a fine particle size; thus, a particle size below 0.3 mm is preferred when preparing the ECCs to achieve a high toughness. The multiple cracking performance (MCP) and the pseudostrain hardening (PSH) of desert sand and ordinary sand with a 0.075–0.3 mm grain size were 2.88 and 2.33, and 8.76 and 8.17, respectively, all of which meet the strength criteria and energy criteria and have similar properties. The tensile strength and tensile deformation of the desert sand group were 4.97 MPa and 6.78%, respectively, and the deformation capacity and strain–strengthening performance were outstanding. It is verified that it is feasible to use desert sand instead of ordinary sand to prepare the ECCs.

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“…By incorporating waste materials or industrial by-products into the manufacturing process of Portland cement, economically and environmentally friendly solutions can be found. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] The annual growth of the construction industry has led to a significant amount of solid waste production, creating further environmental concerns. In summary, although concrete is a fundamental building material, its production has a significant environmental impact.…”

Section: Introductionmentioning

confidence: 99%

“…Cement companies are taking steps to minimize their environmental footprint and transform Portland cement into a sustainable material. By incorporating waste materials or industrial by‐products into the manufacturing process of Portland cement, economically and environmentally friendly solutions can be found 2–18 . The annual growth of the construction industry has led to a significant amount of solid waste production, creating further environmental concerns.…”

Section: Introductionmentioning

confidence: 99%

Hydrochloric acid resistance of mortars incorporating waste glass powder as cementitious materials

Sharifi,

Visrudi

2023

Structural Concrete

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Despite numerous studies conducted on the potential of waste materials as cement substitutes, the resistance of mortars comprising such blended cementitious materials against acidic environments has seldom been investigated. This paper presents an investigation into the potential of waste glass powder (WGP) as a replacement for cement in enhancing the mechanical, and durability of cementitious materials subjected to acidic environments. The study examines the impact of WGP on the resistance of mortar to hydrochloric acid solution attack, with specimens containing 0%, 5%, 10%, 15%, 20%, 25%, and 30% WGP produced as cement substitutes. The tests were conducted on the cement mortar and paste after water curing for 7, 14, 28, 42, and 56 days. Initially, the pozzolanic activity index assessment, fresh density, water absorption, and compressive strengths during water curing times were evaluated. Subsequently, the performance of mortars, when subjected to hydrochloric acid solutions, was assessed, including mass loss, residual compressive strength, visual inspection, and microstructure features during 8 weeks of immersion in hydrochloric acid. The results of the study indicated that the incorporation of WGP led to improved hydrochloric acid resistance in the mortar. Furthermore, an increase in WGP content resulted in a reduced reduction in compressive strength against hydrochloric acid attacks as the ages progressed. The study revealed that the mortar containing 5% WGP as a cement substitute had the highest compressive strength compared to other specimens, and using 10% WGP as a supplementary cementitious material was comparable to the control mixture. Finally, the x‐ray diffraction pattern indicated that the specimen containing 5% WGP had a lower intensity of portlandite peaks than the reference specimen.

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Cementitious mortars containing pozzolana under elevated temperatures

Cited by 12 publications

References 32 publications

Mechanical Properties of Ultra-High Performance Concrete with Coal Gasification Coarse Slag as River Sand Replacement

Mechanical Properties of Ultra-High Performance Concrete with Coal Gasification Coarse Slag as River Sand Replacement

Experimental Study on Toughness of Engineered Cementitious Composites with Desert Sand

Hydrochloric acid resistance of mortars incorporating waste glass powder as cementitious materials

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