Properties of magnesium potassium phosphate cement-expanded perlite composites applied as fire resistance coating

Yuan, Fang; Yin, Xiaohong; Cui, Peng; Wang, Xiaodong; Zhuang, Kunde; Zhu, Ding; Xing, Feng

doi:10.1016/j.conbuildmat.2021.123513

Cited by 16 publications

(3 citation statements)

References 31 publications

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“…The results of OE4, OE2, and OE9 show that the μ p of the control sharply increased to 158.71 mPa·s as the 10% replacement of cement with EP and continued to increase with the increase in replacement level. Since the higher water absorption and open pores of EP particles, EP significantly increased viscosity and reduced fluidity [ 46 , 47 , 48 ]. The results of OE7, OE5, and OE3 revealed that the round shape FACs significantly decreased the viscosity and increased the fluidity.…”

Section: Resultsmentioning

confidence: 99%

Using Fumed Silica to Develop Thermal Insulation Cement for Medium–Low Temperature Geothermal Wells

et al. 2022

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During geothermal energy development, the bottom high-temperature fluid continuously exchanges heat with the upper low-temperature wellbore and the stratum during its rising process. Thermal insulation cement (TIC) can increase the outlet temperature, thus effectively reducing the heat loss of the geothermal fluid and improving energy efficiency. In this study, vitrified microbubbles (VMB) were screened out by conducting an orthogonal test of compressive strength (CS) and thermal conductivity (TC) on three inorganic thermal insulation materials (VMB, expanded perlite (EP), and fly-ash cenosphere (FAC)). Fumed silica (FS) was introduced into the cement with VMBs, as its significant decreasing effect on the TC. Moreover, a cement reinforcing agent (RA) and calcium hydroxide [CH] were added to further improve the CS of TIC at 90 °C. The fresh properties, CS, TC, hydration products, pore-size distribution, and the microstructure of the cement were investigated. As a result, a TIC with a TC of 0.1905 W/(m·K) and CS of 5.85 MPa was developed. The main conclusions are as follows: (1) Increasing the mass fraction of the thermal insulation material (TIM) is an effective method to reduce TC. (2) The CH content was reduced, but the C–S–H gel increased as FS content increased due to the pozzolanic reaction of the FS. (3) As the C–S–H gel is the main product of both the hydration and pozzolanic reactions, the matrix of the cement containing 60% FS and VMBs was mainly composed of gel. (4) The 10% RA improved the cement fluidity and increased the CS of TIC from 3.5 MPa to 5.85 MPa by promoting hydration.

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Section: Resultsmentioning

confidence: 99%

Using Fumed Silica to Develop Thermal Insulation Cement for Medium–Low Temperature Geothermal Wells

et al. 2022

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“…Secondly, and more specifically, the MKPC has a potential in the field of fire protection—it has the potential to take over cement’s role in the given field. For those reasons, new advantageous lightweight materials with advanced fire resistance, thermal properties, and the target to be cheap, non-toxic, and also sustainable, are being developed [ 48 , 49 , 50 , 51 , 52 ].…”

Section: Introductionmentioning

confidence: 99%

Magnesium Potassium Phosphate Cement-Based Derivatives for Construction Use: Experimental Assessment

et al. 2022

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The presented research is focused on the development and testing of the magnesium potassium phosphate cement-based materials (MKPC-based). Firstly, the fresh state properties of the pastes consisting of dead burned magnesia powder, potassium dihydrogen phosphate, setting retarder borax applied in the range of 0–10 wt.%, and batch water were investigated. The aim of testing was to characterize the hydration process in dependence on the borax content. The properties of raw MgO powder were described by chemical composition and particle size distribution. The properties tested in fresh state included shear stress (viscosity), Young’s modulus of elasticity, and temperature; their time dependence was observed. The measurements started immediately after the mixing process. At the age of 14 days, basic structural and mechanical properties of the hardened pastes were obtained. The mixture with 5 wt.% of borax proved to be the most advantageous in terms of setting time, sample integrity, and mechanical strength; therefore, it was chosen as the binder for the following part of the study—MKPC-based mortar development. In the next step, the MKPC paste containing 5 wt.% of borax was supplemented by silica sand aggregate, and the resulting material was marked as a reference. Subsequently, three other mixtures were derived by replacing 100% of quartz sand by lightweight aggregate; namely by expanded glass aggregate, waste rubber from tires, and combination of both in ratio 1:1. The aggregates were characterized by chemical composition (except for the rubber granulate), and loose and compacted powder density. For the resulting hardened composites, basic structural, hygric, strength, and thermal parameters were investigated. The use of lightweight aggregates brought in a considerable decrease in heat transport parameters and low water permeability while maintaining sufficient strength. The favorable obtained material properties are underscored by the fact that magnesia-phosphate is considered to be a low-carbon binder. The combination of magnesia-phosphate binder and recycled aggregate provides a satisfying, environmentally friendly, and thermally efficient alternative to traditional Portland cement-based materials.

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“…It was found that the density and late compressive strength of MKPC mixed with fly ash and silica fume were higher than those of MKPC without fly ash and silica fume under both air and water curing. Fang et al [19] studied the fire resistance performance of MKPC doped with expanded perlite (EP), which included loss by weight (LOW), generated cracks, and microstructural changes. The results revealed the feasibility of the MKPC-EP composite as a coating applied to protect the substrate from fire.…”

Section: Introductionmentioning

confidence: 99%

High-Temperature Resistance of Modified Potassium Magnesium Phosphate Cement

et al. 2022

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To study the high-temperature mechanical properties of potassium magnesium phosphate cement mortar and the high-temperature resistance of its laminates. Potassium magnesium phosphate cement (MKPC) was prepared by using heavy-burning magnesium oxide and potassium dihydrogen phosphate as the main raw materials, borax as the retarder, and compounded with a certain amount of fly ash and silica fume. The effect of the mass ratio of magnesium to phosphorus (M:P), compounded fly ash and silica fume on the setting time and mechanical properties of MKPC was investigated. Furthermore, based on the better M:P, the compressive strength of MKPC mortar was studied after 3 h of constant temperature at 400 °C, 600 °C, and 800 °C, and the effect of fly ash and silica fume on the high-temperature resistance of MKPC was analyzed. The high-temperature resistance of MKPC was further evaluated by analyzing the temperature variation of potassium magnesium phosphate cement laminate during a constant temperature of 650 °C for 3 h. The results showed that the mechanical properties of potassium magnesium phosphate cement were influenced by different raw material ratios, and the mechanical properties of potassium magnesium phosphate cement were optimal when M:P was 2:1, fly ash was 5% and silica fume was 15%. The internal temperature of MKPC laminate increased slowly with time, and its high-temperature resistance was better.

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Properties of magnesium potassium phosphate cement-expanded perlite composites applied as fire resistance coating

Cited by 16 publications

References 31 publications

Using Fumed Silica to Develop Thermal Insulation Cement for Medium–Low Temperature Geothermal Wells

Using Fumed Silica to Develop Thermal Insulation Cement for Medium–Low Temperature Geothermal Wells

Magnesium Potassium Phosphate Cement-Based Derivatives for Construction Use: Experimental Assessment

High-Temperature Resistance of Modified Potassium Magnesium Phosphate Cement

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