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The use of thermal analysis in assessing the effect of temperature on a cement paste
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TLDR
In this article, the effect of temperature in the mineralogical composition of cement hydration products has been studied using thermogravimetric analysis (TGA) and DTG curves, which can be used to determine fire conditions and the consequent deterioration expected in the cement paste.About:
This article is published in Cement and Concrete Research.The article was published on 2005-03-01. It has received 709 citations till now. The article focuses on the topics: Cement & Portlandite.read more
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Synergic effects between mineral admixtures on strength and microstructure of concretes
TL;DR: In this article, the authors evaluated the physical, chemical and synergistic effects of substitution 25% cement in mass by limestone filler (LF), fly ash (FA), and rice husk ash (RHA), in similarity of physical condition (near grain size curves), and compared the different binary and ternary mixtures of concrete after 28 days of wet curing, keeping the ratio water/cement (w/c) constant.
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Laboratory assessment of early-age durability benefits of a self-healing system to cementitious composites
Jialuo He,Jialuo He,Xianming Shi +2 more
Abstract: Shrinkage of cement composites (paste, mortar, grout, or concrete) due to moisture loss during the curing period is a challenge for their durability. In this laboratory study, urea-formaldehyde (UF) microcapsules and polyvinyl alcohol (PVA) microfibres were utilized as a self-healing system to improve the early-age durability of cement mortars by mitigating their total shrinkage during the curing period. Experimental results revealed that the admixed UF microcapsules/PVA microfibres together could mitigate 25% of the total shrinkage during the curing period of 35 days. In addition, this self-healing system could reduce the gas permeability of the mortars by over 75%. The UF microcapsules and PVA microfibres could interfere with the formation of some crystalline hydration products and modify the microstructure of hydrated cement mortar, resulting in slight reductions in the compressive strength (less than 12%) and at some dosages significantly reduced the chloride migration coefficient of the mortars (i.e., 1% 1100+PVA, 2% 700, and 1% 1100). The UF microcapsules mainly affected the pores with a radius between 10 nm and 1000 nm, whereas the PVA microfibers mainly affected the larger pores at the interfacial transition zone .
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Heat transfer model for a cementitious‐based insulation with moisture
TL;DR: In this article, a heat transfer model is proposed to accurately predict the thermal response of cementitious-based fire insulations, considering the effects of the moisture and the decomposition of calcium hydroxide.
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Compressive strength of concrete at high temperatures: a reassessment
TL;DR: In this paper, a reassessment of the subject is given, which considers material and environmental factors/mechanisms influencing the strength of concrete during the heat cycle and after cooling, not all of which necessarily result in strength loss.
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Thermal stability and decomposition mechanisms of ettringite at <120°C
Q. Zhou,Fredrik P. Glasser +1 more
TL;DR: In this article, the decomposition and reformation of ettringite is studied as a function of water vapour pressure and temperature, and the authors make recommendations for the upper safe service limits for ETTringite-based cements.
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Physicochemical, mineralogical, and morphological characteristics of concrete exposed to elevated temperatures
TL;DR: In this paper, the effect of elevated temperatures on the mineralogical changes occurring in the hydrated phases of concrete cubes were studied by measuring ultrasonic pulse velocity (UPV) and consequent deterioration in the compressive strength with increase in temperature.
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Differential scanning calorimetry study of ordinary Portland cement
Wei Sha,E.A. O’Neill,Z. Guo +2 more
TL;DR: In this article, the thermal behavior of hydration products in ordinary Portland cement as a function of age was investigated using differential scanning calorimeter (DSC) and X-ray diffraction analysis.
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Elastic properties of high alumina cement castables from room temperature to 1600°C
TL;DR: In this article, high-alumina refractory castables with compositions in the systems CaO-Al2O3 and CaO−Al 2O3-SiO2 were studied using an ultrasonic technique.