Experimental and Numerical Simulation on the Penetration for Basic Magnesium Sulfate Cement Concrete.

The penetration resistance of the new material Basic Magnesium Sulfate Cement (BMSC) is studied through comprehensive application of an experimental and numerical simulation method. This paper consists of three parts. The first part introduces the preparation of Basic Magnesium Sulfate Cement Concrete (BMSCC) and the study of its dynamic mechanical properties.

Solidification/stabilisation behaviours of Zn in magnesium potassium phosphate cement: Experiments and density functional theory study.

The solidification/stabilisation behaviours of Zn in magnesium potassium phosphate cement (MKPC) have not been thoroughly investigated. Herein, a series of experiments and a detailed density functional theory (DFT) study were conducted to investigate the solidification/stabilisation behaviours of Zn in MKPC. The results showed that the compressive strength of MKPC reduced with the addition of Zn because the formation of MgKPO·6HO (the main hydration product in MKPC) was delayed with the addition of Zn, as discovered by the crystal characteristics, and because Zn exhibited a lower binding energy in MgKPO·6HO compared to Mg, as revealed by DFT results.

Optimization of Magnesium Potassium Phosphate Cements Using Ultrafine Fly Ash and Fly Ash.

The effect of ultrafine fly ash (UFA) and fly ash (FA) on the physical properties, phase assemblage, and microstructure of magnesium potassium phosphate cement (MKPC) was investigated. This study revealed that the UFA addition does not affect the calorimetry hydration peak associated with MKPC formation when normalized to the reactive components (MgO and KHPO). However, there is an indication that greater UFA additions lead to an increased reaction duration, suggesting the potential formation of secondary reaction products.

Immobilization of Zn(Ⅱ) and Cu(Ⅱ) in basic magnesium-sulfate-cementitious material system: Properties and mechanism.

To solve the environmental problems caused by heavy metal pollution, a new cementitious material (basic magnesium sulfate cement, BMSC) was developed for the solidification of Cu/Zn. First, the effects of different amounts of Cu/Zn on the properties (compressive strength, setting time, pH, and leaching toxicity) of the BMSC were investigated. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) were used to investigate the effects of different amounts of Cu/Zn on the phase and microstructure of BMSC.

Preparation of magnesium potassium phosphate cement using by-product MgO from Qarhan Salt Lake for low-carbon and sustainable cement production.

Herein, to reduce CO emissions and energy consumption and to promote the recycling of waste resources, two types of boron-containing MgO by-products, which were obtained by lithium extraction from Qarhan Salt Lake, China, were used as substitutes for dead-burned MgO to prepare magnesium phosphate potassium cement (MKPC) as a rapid repair material. First, the phase composition and particle-size distribution of the MgO by-product were investigated. The effects of different MgO sources, molar ratio of MgO to KHPO (M/P), and curing age on the setting time and mechanical properties of MKPC were then studied.

Designing novel magnesium oxysulfate cement for stabilization/solidification of municipal solid waste incineration fly ash.

Municipal solid waste incineration (MSWI) fly ash is a typical hazardous waste worldwide. In this study, an innovative magnesium oxysulfate cement (MOSC) binder was designed for stabilization/solidification (S/S) of MSWI fly ash, focusing on the interactions between MOSC binder and typical metallic cations (Pb)/oxyanions (AsO). Experimental results showed that Pb and As slightly inhibited the reaction of high-sulfate 5MS system but significantly suppressed the reaction process of low-sulfate 10MS system.

Properties and microstructure of basic magnesium sulfate cement: Influence of silica fume.

Silica fume (SF) as an important supplementary cementitious material has been widely used in Portland cement, but few published articles have reported on the effect of SF on the performance and hydration mechanism of basic magnesium sulfate cement (BMSC). In the present work, the properties, microstructure and hydration mechanism of BMSC influenced by SF was studied systematically. The results show that the setting time and compressive strength of BMSC may increase with the increase of SF content, while the hydration heat will decrease with the increase of SF content.

High-efficiency and low-carbon remediation of zinc contaminated sludge by magnesium oxysulfate cement.

Electroplating sludge is classified as a hazardous waste due to its extremely high leachability of potentially toxic elements. This study concerns the use of magnesium oxysulfate cement (MOSC) for the stabilisation/solidification (S/S) of Zn-rich electroplating sludge. According to X-ray diffraction and thermogravimetric analyses, Zn was mainly immobilised through both chemical interaction and physical encapsulation in the MOSC hydrates of 5Mg(OH)·MgSO.

Investigation on the Corrosion Behavior of Steel Embedded in Basic Magnesium Sulfate Cement Concrete: An Attempt and Challenges.

Basic magnesium sulfate cement is a type of green high-performance cementitious material. In order to exert its performance advantages and expand its application field, it is urgent to study the problem of steel corrosion in basic magnesium sulfate cement concrete (BMSCC). In this paper, linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS) were used to study the corrosion behavior of steel bars in different strength grades of BMSCC in seawater.

Study on the injectability of a novel glucose modified magnesium potassium phosphate chemically bonded ceramic.

A novel magnesium potassium phosphate chemically bonded ceramic (MKPCBC) was prepared as a byproduct of boron-containing magnesium oxide (B-MgO) after extracting LiCO from salt lakes. In this work, the influence of glucose on the properties of MKPCBC, such as the setting time, compressive strength and hydration heat, was investigated. In addition, we studied the effect of the magnesium-phosphate ratio (M/P) and liquid-solid ratio (L/S) on the injectability of MKPCBC.