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1. Introduction. Cement hydration is a complex process, as cements normally consist of several anhydrous phases that react at different rates, forming different hydrates [1, 2].Together the hydrates make up the cement paste, a porous material that grows into the water-filled spaces between the solids (cement and aggregate grains) as …
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Polymer compounds have become a popular choice for the synthesis of novel products and are being used in cementitious mixtures principally for altering the properties in the fresh state and as repair materials. These polymers are used in various combinations. Their interaction with cement is worth studying because its hydration, followed by …
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Learn about the five stages of cement hydration, the mechanisms of hydration, the heat of hydration, and the products of hydration. Find out …
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The higher amount of total heat release at higher w/c ratio can be attributed to larger inter-particle space between cement grains that allow hydration product to grow as well as higher free water content in the pore space that facilitate further hydration reaction during later stages; these effects were much smaller at 15 °C due to ...
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wn = 0.24a g/g of original cement . where a = degree of hydration and wn = nonevaporable water . wg = 0.18a g/g of original cement. where wg = gel water or evaporable water Other relationships for volume of hydration products and porosity are available (see p. 105). Based on these, a minimum water/cement ratio relationship for …
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Schematic illustration of hydration process a few minutes (a) or several hours (b) after mixing a paste without seeding. The hydration product nucleates on the surface of the particles and grows toward the pore space. After some hours, the thickness of the hydration product limits further grows, which leads to a high volume of capillary porosity.
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The observed effects are caused by the processes of dispersion and hydration of cement particles and crystallization of cement hydration products. Three types of harmonic frequencies are detected for the heat formation, viz. 1–3 vibrations per minute, ~12 h, and a several days vibration period. The heat formation-based analysis of …
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The current state of knowledge of cement hydration mechanisms is reviewed, including the origin of the period of slow reaction in alite and cement, the …
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Cement hydration reaction generates hydration products, such as calcium silicate hydrate (C-S-H) [197], portlandite [11], gypsum and ettringite [99]. The main characteristic of any pozzolanic material is the presence of soluble SiO 2 .
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Although CNTs are known to be non-reactive with cement hydration products (unlike nano-SiO 2), the effects of adding CNTs on cement hydration should be carefully considered during the simulation. The proposed model involves (1) multiphase voxels for considering CNTs, (2) an algorithm for hydration (dissolution, diffusion, and …
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Cement hydration refers to the chemical reaction between cement and water that leads to the hardening and setting of cement and other cementitious …
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Caption: The high temporal and spatial resolution Raman imaging technique opens opportunities to answer millennia-old questions regarding cement chemistry. This high-resolution Raman image shows the hydration of alite (white) forming C-S-H (blue) and portlandite (red). Other components are belite (green) and calcite (yellow).
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This is due to the exothermic process in the reaction between cement and water (called hydration). Measuring the concrete temperature over time enables you to know how far the concrete is in …
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Similarly, a fundamental approach to understanding cement hydration would involve breaking the problem down to the study of the kinetics. Mechanisms of C 3 S or alite hydration. The rates of hydration of (triclinic) C 3 S, alite, and even PC have long been observed to vary with time by orders of magnitude in a complicated, nonmonotonic …
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The products of cement hydration are crucial components that contribute to the strength and durability of concrete. The primary products include: Calcium Silicate Hydrate (C-S-H) Gel: This gel is the primary product of …
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The hydration products are the same except that the proportion of CH produced is about one-third of that obtained on hydration of C 3 S. Tricalcium aluminate (3CaO.Al 2 O 3 = C 3 A) The initial reaction of C 3 A with water in the absence of gypsum is vigorous, and can lead to "flash set" caused by the rapid production of the hexagonal ...
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An in-depth understanding of cement hydration is required for the development of environmentally friendly cement and consequently the reduction of …
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Learn how cement reacts with water to form calcium silicate hydrate, calcium hydroxide, ettringite, monosulfate and other hydration products. See how the hydration process affects concrete strength, heat evolution …
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Cement hydration process can be considered to be consisting of three steps: (1) the dissolution of the clinkers and other constituents in water, (2) nucleation and growth of the hydrated products through precipitation from the saturated pore solution containing dissolved ions, and (3) diffusion of water and the dissolved ions through the ...
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In this work, the optimal conditions of the synthesis of eco-friendly cement by using industrial wastes as well as the peculiarities of its early stage hydration were investigated. The eco ...
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The changes of microstructure during the hydration process (according to []): a unhydrated cement grain.b after 10 min—gel rich in alumina precipitates on cement grains; short AFt rods nucleate in the solution and at edge of gel.c after 10 h the C–S–H outer product begins to form on AFt rods leaving a gap between the surface of grain …
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Cement hydration is a key factor affecting the hydro-mechanical coupling behaviour of cement-treated materials. As a hydraulic cementing medium, during hydration, cement …
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The average density of the Portland cement hydration products was studied on compacts having the initial porosity ranging from 28.4% to 34.1%, and made of cement which contained no gypsum and had the fineness (Blaine) of 2,030, 3,290 and 4,570 sq.cm per g. Results indicated that the average density increased with the …
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Cement hydration is a key factor affecting the hydro-mechanical coupling behaviour of cement-treated materials. As a hydraulic cementing medium, during hydration, cement …
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The hydration products begin to accumulate on the outer periphery of the nucleus of hydrated cement particles. This deposition is a slow reaction and takes around 2 to 5 hours. It is called induction or …
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The cement hydration products serve as a bonding agent between the emulsion and the aggregate particles and help to strengthen the overall bond. Moreover, the hydration products contribute to enhanced stiffness and strength of the mixture, leading to improved resistance against shear deformation and fatigue [9].
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Furthermore, the high pozzolanic activity of silica fume also consumes Ca(OH) 2 in cement hydration products, contributing to further generating C–S–H gel and increasing its polymerization. In order to reduce the particle gap between cement particles, silica fumes act as a microaggregate and fill pores among cement particles. ...
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If there was abundant fluorine in shotcrete, it might leach out and pollute the soil or migrate to corrode the reinforcement.Therefore, this research mainly investigated the basic properties of high-fluorine alkali free liquid accelerator (HF-AFA) and its occurrence forms in cement hydration products.The macro-test results showed that with the …
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Moon et al. [142] reported experimentally that the bulk modulus of monocarboaluminate (54 GPa) is significantly higher than any other hydration products in concrete. In addition, Moon et al. [143] provide a detailed analysis of the full elastic tensors and mechanical properties of the crystal structure computed by first-principles methods …
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The influence of chemical nature of polyvinyl alcohol (PVA) on the microstructure of cement hydration products was investigated. Thermal analysis, X-ray diffraction, Si 29 nuclear magnetic resonance (NMR), and scanning electron microscope were used to explore the microstructure and content of cement hydration products. …
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