scholarly journals Influence and Mechanism Research of Hydration Heat Inhibitor on Low-Heat Portland Cement

2021 ◽  
Vol 8 ◽  
Author(s):  
Fujie Jia ◽  
Yan Yao ◽  
Jingyu Wang
Keyword(s):  
Compressive Strength ◽  
Sustained Release ◽  
Portland Cement ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Setting Time ◽  
Hydration Heat ◽  
Adiabatic Temperature Rise ◽  
Mechanism Research

A kind of microcapsule sustained-release–type hydration heat inhibitor (MSR) was prepared. The effect of MSR on semi-adiabatic temperature rise, setting time, and strength of low-heat Portland cement was investigated. Microcalorimetry, XRD, SEM, and TG-DSC were used to investigate the mechanism of MSR on hydration of low-heat Portland cement. The results showed that the MSR had good regulating effect on hydration of low-heat Portland cement. When the dosage of MSR was 0.3%, the heat release rate decreased by 10% and the peak temperature decreased by 52%. The 3D compressive strength decreased by 50%, and the 28-day strength was the same as control. The MSR can delay the hydration of low-heat Portland cement by inhibiting the heat release rate of C2S and C3S minerals.

Portland Cement Based Lightweight Multifunctional Matrix with Different Kind of Additives Containing SiO2

2014 ◽  
Vol 604 ◽  
pp. 305-308 ◽  
Author(s):  
Ina Pundienė ◽  
Modestas Kligys ◽  
Jurga Šeputytė-Jucikė
Keyword(s):  
Compressive Strength ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Dynamic Viscosity ◽  
Building Materials ◽  
Hydration Process ◽  
Aerated Concrete ◽  
Wetting Heat ◽  
Pozzolanic Properties

Additives containing SiO2 (ACS) and having pozzolanic properties such as metakaolin (MK), microsilica (MS) and milled autoclaved aerated concrete waste (MAACW) are promising materials for partially replacement of Portlandcement (PC) in matrix of lightweight building materials. Studies have shown that SA effects on the hydration process of PC matrix. The highest wetting heat release rate values were obtained using MS additive, and the lowest a mix of MS and MK additives. In a mix with both MS and MK additives, the maximal value of heat release rate was reached after 10 h and in a mix with MS additive after 13 h. MS additive extends while MK additive accelerates the hydration process of PC. The most effective plasticizer (P) was chosen according to the study of dynamic viscosity (DV) of PC matrix. It was fixed that surfactant (SU) in amount of 0.03 % (from PC) reduces the density of matrix about 30 % compared with the density of matrix without SU. Increased quantity of MAACW (from 5 to 15 % from PC) causes in increase of compressive strength of PC matrix (after 28 days curing) from 19 to 47 MPa.

scholarly journals Evaluation of the green coconut fiber compatibility with cement by using different calculation methods

2018 ◽  
Vol 9 (7) ◽  
pp. 171-187
Author(s):  
Maria Lidiane Marques ◽  
Fermin De la Caridad Garcia Velasco ◽  
Francisco Heriberto Martínez Luzardo ◽  
Felix Mas Milian ◽  
Fabiane Alexsandra Andrade de Jesus ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Heat Release ◽  
Release Rate ◽  
Calculation Method ◽  
Critical Review ◽  
Basic Parameter ◽  
Calculation Methods ◽  
Coconut Fiber ◽  
Type K

Using all the different methods reported in the literature, the compatibility of coconut green fiber with Portland cement in five different compounds was evaluated. For each trace, the mixtures hydration curves (temperature x time) were obtained by the use of type K thermocouples and an analog signal receiver. Based on a unique set of experiments with coconut fiber, a comprehensive critical review of the methods reported in the literature was performed to evaluate fiber-cement compatibility. Contradictory results about compatibility classification were obtained using different compatibility equations. The correlations between compatibility and compressive-strength essays results were considered to support our choice of the best method of compatibility calculation. Greater sensitivity to capture the differences in the compositions of mixtures and a higher correlation with the compressive strength of composites revealed that the CX calculation method, which considers the heat release rate as a basic parameter, presented more realistic results.

Effect of Polyacrylic Acid on Retarding Action and Property of Gypsum Plasters

2014 ◽  
Vol 638-640 ◽  
pp. 1526-1530
Author(s):  
Jia Yu Zhan ◽  
Wan Min Li ◽  
Ning Luo ◽  
Jun Gu
Keyword(s):  
Mechanical Property ◽  
Compressive Strength ◽  
Heat Release ◽  
Acid Concentration ◽  
Polyacrylic Acid ◽  
Setting Time ◽  
Hydration Heat ◽  
Carboxylic Group ◽  
Mass Ratio

Polyacrylic acid was synthesized and used as a retarder additive to prolong the setting time of gypsum plasters. The gypsum paste with the polyacrylic acid at the concentration of 0, 0.1%, 0.2%, 0.3%, 0.4% and 0.5% was studied. The water/gypsum mass ratio was 0.56. The influence of polyacrylic acid concentration on the initial and finial setting time, hydration temperature, morphology of hardened gypsum and mechanical property were extensively investigated. The results show that polyacrylic acid is favorable to increase the setting time which was associated with the reaction of carboxylic group and calcium from the hemihydrate dissolution. The morphology of hardened gysum varied when polyacrylic acid is used. The increase concentration of polyacrylic acid results in a decrease in hydration heat release, flexural and compressive strength.

Investigation on Hydration Characteristics of Zinc-Doped Portland Cement Pastes

2010 ◽  
Vol 168-170 ◽  
pp. 623-627 ◽  
Author(s):  
Xiang Guo Li ◽  
Xiao Bo Yin ◽  
Bao Guo Ma ◽  
Bei Wu ◽  
Quanbin Chen ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Setting Time ◽  
Hydration Product ◽  
Hydration Heat ◽  
Cement Pastes ◽  
Ion Concentrations ◽  
Zn Concentration ◽  
Zinc Salts ◽  
Hydration Characteristics

Compressive strength, setting time, hydration heat and hydration product were investigated to evaluate the effects of Zn2+ ion concentrations and the anion of zinc salts on the hydration characteristics of Portland cement paste. The results show that the hydration characteristics of zinc-doped cement pastes depend on Zn2+ ion concentrations and the anion of salts. With the incorporation of ZnCl2, the hydration heat, exothermic rate and the early-age strength of cement pastes were reduced, the arrival time of the highest temperature was delayed, and little negative influences on the compressive strength at 28 days were observed. The total hydration did not decrease incorporating ZnSO4; the hydration exothermic process was delayed. There were little negative influences on the compressive strength of the samples at 3 days and 28 days. Moreover, for the samples with the same Zn concentration, the retardation effect of ZnCl2 samples was stronger than that of ZnSO4 samples.

Scale Modeling on the Effect of Air Velocity on Heat Release Rate in Tunnel Fire

2008 ◽  
Vol 18 (2) ◽  
pp. 111-124 ◽  
Author(s):  
C. Chen ◽  
L. Qu ◽  
Y. X. Yang ◽  
G. Q. Kang ◽  
W. K. Chow
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Air Velocity ◽  
Tunnel Fire ◽  
Scale Modeling

scholarly journals Effect of Waste Glass on the Properties and Microstructure of Magnesium Potassium Phosphate Cement

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2073
Author(s):  
Qiubai Deng ◽  
Zhenyu Lai ◽  
Rui Xiao ◽  
Jie Wu ◽  
Mengliang Liu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Glass Powder ◽  
Setting Time ◽  
Potassium Phosphate ◽  
Heat Of Hydration ◽  
Waste Glass ◽  
Hydration Heat ◽  
Magnesium Potassium Phosphate Cement ◽  
The Matrix ◽  
Powder Content

Waste glass is a bulk solid waste, and its utilization is of great consequence for environmental protection; the application of waste glass to magnesium phosphate cement can also play a prominent role in its recycling. The purpose of this study is to evaluate the effect of glass powder (GP) on the mechanical and working properties of magnesium potassium phosphate cement (MKPC). Moreover, a 40mm × 40mm × 40mm mold was used in this experiment, the workability, setting time, strength, hydration heat release, porosity, and microstructure of the specimens were evaluated. The results indicated that the addition of glass powder prolonged the setting time of MKPC, reduced the workability of the matrix, and effectively lowered the hydration heat of the MKPC. Compared to an M/P ratio (MgO/KH2PO4 mass ratio) of 1:1, the workability of the MKPC with M/P ratios of 2:1 and 3:1 was reduced by 1% and 2.1%, respectively, and the peak hydration temperatures were reduced by 0.5% and 14.6%, respectively. The compressive strength of MKPC increased with an increase in the glass powder content at the M/P ratio of 1:1, and the addition of glass powder reduced the porosity of the matrix, effectively increased the yield of struvite-K, and affected the morphology of the hydration products. With an increase in the M/P ratio, the struvite-K content decreased, many tiny pores were more prevalent on the surface of the matrix, and the bonding integrity between the MKPC was weakened, thereby reducing the compressive strength of the matrix. At less than 40 wt.% glass powder content, the performance of MKPC improved at an M/P ratio of 1:1. In general, the addition of glass powders improved the mechanical properties of MKPC and reduced the heat of hydration.

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