Article
Construction & Building Technology
Shaokun He, Lin Yang, Guotao Hu, Jianxin Cao
Summary: Phosphate impurities in phosphogypsum can be efficiently removed through a two-step crystal transformation method, which also rebuilds the crystal structure of gypsum. The use of modified phosphogypsum as a cement additive can significantly improve the properties of cement.
JOURNAL OF BUILDING ENGINEERING
(2023)
Review
Construction & Building Technology
Xiangrui Meng, Yu Jiang, Bing Chen, Liyan Wang
Summary: This paper provides a comprehensive literature review of 146 papers published from 1970 to 2023 on the solidification and hardening of magnesium phosphate cement (MPC). It analyzes the effects of raw material properties and ratios, temperature variations, retarder and admixture contents on the setting time of MPC-based materials, and summarizes the approaches to regulating the solidification and hardening. The paper also focuses on the mechanism of the effects of mixing proportion and admixtures on the solidification and hardening of MPC.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Construction & Building Technology
Beixing Li, Long Li, Xiao Chen, Yu Ma, Mingkai Zhou
Summary: This study comprehensively modified phosphogypsum using carbide slag, circulating fluidized bed (CFB) fly ash, and other solid wastes, and investigated the influence of material ratio and aging time on the modification effect. The modification mechanism of carbide slag and CFB fly ash on phosphogypsum and the effect of modified phosphogypsum on the hydration characteristics of Portland cement were revealed. The results show that the modified phosphogypsum effectively reduces the contents of soluble phosphorus and soluble fluorine, increases the pH value, enhances the strength of phosphogypsum, and improves the retardation effect of Portland cement.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Construction & Building Technology
Yongrui Wang, Hong Huo, Bing Chen, Qi Cui
Summary: In this study, a phosphogypsum-based geopolymer (PBG) cement was created by mixing beta-hemihydrate phosphogypsum (beta-HPG), slag, fly ash (FA), and alkali activator. The effects of slag and FA content, citric acid and sodium metasilicate dosage, and water addition process were investigated. The results showed that the cement could achieve a 28-day unconfined compressive strength (UCS) exceeding 60 MPa with a reasonable mix proportion. The main hydration products of the PBG cement were dihydrate phosphogypsum, ettringite, and C-S-H gel, which collectively contributed to its strength.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Construction & Building Technology
Gang Zheng, Jianyou Huang, Yu Diao, Aoyang Ma, Yiming Su, Hao Chen
Summary: The study developed a slow-setting cement-based grouting paste (SCGP) for capsule grouting technology (CGT), optimizing material composition and adjusting water-cement ratio and bentonite content to extend initial setting time, resulting in excellent performance for CGT.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Green & Sustainable Science & Technology
Kang Gu, Bing Chen, Wanli Bi, Yan Guan
Summary: This study evaluated the impact of phosphogypsum (PG) and flue gas desulfurization gypsum (FGDG) on the performance of magnesium oxychloride cement (MOC) by replacing MgO powder with waste gypsum. Results showed that PG incorporation improved water resistance but decreased compressive strength of MOC. Phosphate impurities in untreated PG promoted the hydration product formation.
JOURNAL OF CLEANER PRODUCTION
(2021)
Article
Construction & Building Technology
Yifan Xie, Tao Sun, Zhonghe Shui, Chao Ding, Wanmin Li
Summary: This study investigates the effects of carbonation on the microstructure of phosphogypsum-based supersulfated cement paste at different CO2 concentrations. The results show that carbonation significantly increases the porosity and pore size of the paste, leading to changes in the main hydration products and formation of carbonation products.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Chemistry, Physical
Sukanta K. Mondal, Adam Welz, Carrie Clinton, Kamal Khayat, Aditya Kumar, Monday U. Okoronkwo
Summary: This study presents a novel and reliable rheological method for quantifying the workability of calcium sulfoaluminate (CSA) cement pastes modified with citric acid and polycarboxylate ether (PCE)-based superplasticizer. The method can characterize the interaction or co-influence of multiple admixtures on early-age properties of the cement paste and provide a quantitative rheological protocol for determining the workability and a novel approach to material selection and mixture design.
Article
Engineering, Environmental
Xiaoliang Ding, Yi Li, Jie Chen, Xingyu Huang, Lu Chen, Zhijun Hu
Summary: In this study, finished leather waste was used to obtain collagen protein hydrolysate (CPH) with high protein content, and the feasibility of using CPH as a gypsum retarder was investigated. The results showed that CPH exhibited a satisfactory retarding performance comparable to commonly used gypsum retarders, citric acid (CA) and sodium hexametaphosphate (SHMP), and the retarding performance of CPH on gypsum improved with increased dosage.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2023)
Article
Biotechnology & Applied Microbiology
Lei He, Zhen Wang, Wen-bin Gu
Summary: Cement-based stabilization/solidification (S/S) technology is an effective and economical remediation method for immobilizing heavy metals in contaminated soils. This study found that the strength of solidified soil decreases with the increase of freezing and thawing cycles, and the toxicity leaching of the solidified soil is linearly related to porosity.
ENVIRONMENTAL TECHNOLOGY & INNOVATION
(2021)
Article
Construction & Building Technology
Shengnian Wang, Zewei Chen, Haiyan Jiang, Jun Su, Zhijian Wu
Summary: Reducing cement consumption and eliminating the residual by-product of cement hydration can improve the mechanical performance and economic benefits of problematic soils in underground engineering practices. The study used red mud and phosphogypsum as additives in cemented silty sands. The results show that red mud and phosphogypsum can replace up to 1/3 of cement consumption in soil stabilization. The composite binder of cement, red mud, and phosphogypsum achieved superior mechanical performance in silty sands stabilization. The addition of red mud and phosphogypsum compacted the internal structure of the soil and resolved the defects caused by the by-products of cement hydration.
JOURNAL OF BUILDING ENGINEERING
(2023)
Review
Green & Sustainable Science & Technology
Xiantao Qin, Yihu Cao, Haowei Guan, Qisheng Hu, Zhihao Liu, Jing Xu, Bo Hu, Zeyu Zhang, Rong Luo
Summary: This review analyzes the utilization status and development trend of phosphogypsum (PG) in civil engineering, emphasizing its importance. The chemical compositions of different PG and pretreatment methods are compared and analyzed. The utilization of PG in cement retarder, building materials, cement raw materials, concrete raw materials, cementitious materials, and fillers and modifiers is summarized. Future research should focus on improving the reactivity and long-term stability of PG and promoting the large-scale, environment-friendly, and resourceful utilization of PG-based materials.
JOURNAL OF CLEANER PRODUCTION
(2023)
Article
Construction & Building Technology
Yupeng Cao, Jing Zhang, Zengfeng Zhao, Junxia Liu, Hui Lin
Summary: This study investigates the effect of organic matter content and curing temperature on the development of strength in cement-solidified dredged sludge (CSC). The results show that increasing organic matter content decreases the compressive strength of CSC. However, increasing the curing temperature has little effect on the strength growth rate. Higher curing temperature can enhance the early strength growth rate and shorten the curing age for CSC containing organic matter.
Article
Green & Sustainable Science & Technology
Ziyan Wang, Zhonghe Shui, Tao Sun, Xiaosheng Li, Mingzhong Zhang
Summary: This paper investigates the effect of metakaolin on early hydration, phase assemblages, and mechanical properties of excess-sulphate phosphogypsum cementitious materials. It is found that metakaolin can shorten the setting time and increase the compressive strength. When the dosage of metakaolin is below 20%, there is an increase in ettringite and highly disordered C-(A)-S-H gel, leading to a significant increase in compressive strength. However, exceeding 20% metakaolin dosage reduces the hydration degree at the late stage.
JOURNAL OF CLEANER PRODUCTION
(2022)
Article
Construction & Building Technology
Md Mostofa Haider, Guoqing Jian, Tuhua Zhong, Hui Li, Carlos A. Fernandez, Leonard S. Fifield, Michael Wolcott, Somayeh Nassiri
Summary: In this pioneering study, waste shrimp shells were used to produce chitin nanocrystals and nanofibers, which were then evaluated in cement paste. The results showed that chitin nanocrystals delayed the final set time of the cement paste, while chitin nanofibers had a smaller effect. Additionally, the addition of chitin nanocrystals significantly increased the flexural and compressive strength of the cement paste.
CEMENT & CONCRETE COMPOSITES
(2022)
