Enhancement of sintered sludge ash-modified cement paste with CaSO4 and CaCl2

Zhao, Qingxin; Lv, Tong; Liang, Hui; Zhang, Juntao; Zhang, Jinrui

doi:10.1016/j.conbuildmat.2023.131245

Cited by 19 publications

(3 citation statements)

References 56 publications

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“…Measurements of weight change and relative compressive strength were conducted to assess the performance of the mixtures under acidic conditions. The control mix had the weakest resistance to the H 2 SO 4 attack, showing a reduction in compressive after 28 days at 20 • C. According to the literature, gypsum and ettringite are the two main cementitious materials that show potential effects against attack by sulfuric acid [62][63][64]. When calcium hydroxide and the binder gel are attacked over an extended period of time by sulfate ions, gypsum and ettringite are produced.…”

Section: Acid Resistancementioning

confidence: 99%

Effect of Biochar and Sewage Sludge Ash as Partial Replacement for Cement in Cementitious Composites: Mechanical, and Durability Properties

Mosaberpanah,

Olabimtan,

Balkis

et al. 2024

Sustainability

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With the significant pace of industrialization, the emission of carbon dioxide (CO2) through cement manufacture, as well as from developed environments, will undoubtedly rise yearly. Biochar as a byproduct of biomass pyrolysis can be utilized in concrete to partially replace cement. Because of its ecological and economic benefits, such as carbon sinks or carbon capture, low thermal conductivity, chemical resistance, and low thermal properties, biochar has risen in popularity in recent years. On the other hand, the possibility of using sludge ash as a cement substitute in the process of making mortar has recently attracted increasing interest. The effectiveness and acceptability of using pine cones as a byproduct of biochar and sludge ash, a byproduct of wastewater treatment, to produce mortar in place of cement are being intensively explored. The integration of biochar and sludge ash into cementitious materials is a possible approach for pollution reduction by replacing Portland cement and reducing collection and disposal in landfills. In order to create high-performance mortar, this study experimentally explores the impacts of combining biochar at an optimal of 6% and sludge ash at optimal of 10%. It analyzes the rheological, mechanical, and durability attributes across curing times of 7 and 28 days in both wet and dry environments, while keeping a constant temperature of 20 °C. As a result, at 28 days, every blend was higher compared to baseline mixture at 7 days. Increases of 19.52% and 13.78%, as well as 24.76% and 21.68%, were seen in the mixtures with 5% and 10% sludge ash (SA) at 28 days compressive strength. With percentage increments for both 7 days and 28 days of 6.6% and 30.9% and 2.2% and 14.1%, the binary blend utilizing BC3SA10 and BC3SA5 significantly outperformed the reference mix. In mortar, the use of biochar could reduce capillary absorption. In addition, its inclusion fastens the rate of hydration of the cement and prevents shrinkage cracks in the mix. The current study concentrates on the significant features of biochar and sludge ash that have an impact on cementitious materials performance. The fresh as well as hardened properties of various concrete and mortar mixes after the replacement of cement with biochar and sludge ash components have been extensively reviewed based on the research results. In a nutshell, biochar and sludge ash materials are an excellent alternative for cement in construction.

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Section: Acid Resistancementioning

confidence: 99%

Effect of Biochar and Sewage Sludge Ash as Partial Replacement for Cement in Cementitious Composites: Mechanical, and Durability Properties

Mosaberpanah,

Olabimtan,

Balkis

et al. 2024

Sustainability

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“…It was believed that the band at 1117cm -1 was caused by the asymmetric stretching vibration of the S-O bond in SO 4 2-, which was considered to be the fingerprint peak of Ettringite (Zhao The peak here was more obvious for the spectrum of 50% content, which was guessed because the large content of SSA delayed the cement hydration process excessively, the formation of the skeleton structure of the hydration product was slower and the water consumption was slower, so it was easier to carbonization reaction occurs. The bands appeared around 1,642 cm −1 and 3,448 cm −1 were caused by the stretching and bending vibrations of the O-H bond of the structural water in the hydration product (Higl et al, 2021;Zhao et al, 2023). It could be seen that with the increase of SSA content, the peak intensity at 3,448 cm −1 decreased slightly, and the peak intensified at 1,642 cm −1 was the strongest at 10% content, indicated that the hydration products of the specimen with 10% SSA content were more and the hydration process was more sufficient.…”

Section: Hydration Productmentioning

confidence: 99%

Insights on the performance of sintered silt ash-blended cement: experiments and thermodynamic simulation

Li,

Liu,

Zhang

et al. 2023

Front. Mater.

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The dredged silt exposed to the air is highly expected to be used to replace cement in large quantities due to its richness in aluminosilicates, which is in line with the dual-carbon background. Herein, a systematic exploration on the basic properties and hydration products of sintered silt ash-blended (SSA-blended) cement is conducted, using experiments and thermodynamic simulations. The results show that in the process of adding SSA to 50%, the compressive property and chloride ion permeation resistance are enhanced first and then weakened, whereas the flexural property is weakened gradually. Among them, with the addition of 10% SSA, the compressive strength can reach 65.2 MPa and the electric flux is 37.3% lower than that of Portland cement (PC), and the chloride ion permeability is rated as the lowest. As SSA increases, the FTIR spectra show that the reduction rates of bound water, ettringite and Ca(OH)2 are accelerated gradually; SEM observation shows that the cement-based gelling skeleton has undergone a transition from dense to loose; the thermodynamic simulation results show that C-S-H increases first and then decreases, implying that SSA has a certain pozzolanic activity. In addition, the evolution laws of other hydration products are highly consistent with the analysis results of FTIR and SEM.

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“…The existence of mineral components in dredged silt makes it possible to use it in inorganic cementitious materials. At present, many scholars have conducted systematic research on the modification of Portland cement with silt [39][40][41][42][43][44]; however, there have been few studies on the modified MPC of dredged silt.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Properties and Hydration Degree of Magnesium Potassium Phosphate Cement Modified by Sintered Silt Ash

Zhang,

Yang,

Luo

et al. 2023

Materials

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The effective utilization rate of river-dredged silt was extremely low, and common disposal methods such as dumping it into the ocean have already threatened the ecological environment. To demonstrate that dredged silt can be used as a mineral admixture to modify magnesium potassium phosphate cement (MKPC), the mechanical properties and hydration degree of sintered silt ash (SSA)-blended MKPC in the early stage of hydration were studied systematically in this paper, with MKPC as the reference group. The mechanical experiment results showed that in the process of increasing the SSA content to 25%, the compressive strength first increased and then decreased. Among the samples, the compressive strength of cement aged by 1d and 3d with 15% content was the highest, which increased by 11.5% and 17.2%, respectively, compared with the reference group. The setting time experiment found that with the increase in SSA content, the hydration reaction rate of MKPC slowed down significantly. Its effect of delaying hydration was most obvious when the SSA content was 10–15%. The X-ray diffraction pattern showed that there was no large amount of new crystalline substances formed in the hydration product. The results obtained by scanning electron microscopy show that the microstructure tended to be denser and the hydration products tended to be plump when the SSA content was in the range of 0–15%. The non-contact electrical resistivity experiment showed that the addition of SSA delayed the early hydration of MKPC. Combined with the above experiment results, it was found that when the content of SSA was less than 15%, it not only delayed the early hydration of MKPC, but also deepened its hydration degree.

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Enhancement of sintered sludge ash-modified cement paste with CaSO4 and CaCl2

Cited by 19 publications

References 56 publications

Effect of Biochar and Sewage Sludge Ash as Partial Replacement for Cement in Cementitious Composites: Mechanical, and Durability Properties

Effect of Biochar and Sewage Sludge Ash as Partial Replacement for Cement in Cementitious Composites: Mechanical, and Durability Properties

Insights on the performance of sintered silt ash-blended cement: experiments and thermodynamic simulation

Mechanical Properties and Hydration Degree of Magnesium Potassium Phosphate Cement Modified by Sintered Silt Ash

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