scholarly journals QUANTITATIVE HYDRATED SILICATE MONOMER IN HYDRATION OF ALITE AND CONSIDERATION OF CEMENT HYDRATION MECHANISM

2015 ◽  
Vol 69 (1) ◽  
pp. 2-9
Author(s):  
Toyoharu NAWA ◽  
Tomotaka AWAMURA ◽  
Junbum PARK ◽  
Yuka MORINAGA
Keyword(s):  
Cement Hydration ◽  
Hydrated Silicate ◽  
Hydration Mechanism

The Mechanism of Mineral Admixture in Cement Hydration

2012 ◽  
Vol 450-451 ◽  
pp. 1528-1531
Author(s):  
Mei Li Zhao
Keyword(s):  
Cement Paste ◽  
High Performance ◽  
Cement Hydration ◽  
High Performance Concrete ◽  
Cement Mortar ◽  
Sem Analysis ◽  
Mineral Admixture ◽  
Hydration Mechanism ◽  
Curing Period ◽  
Durability Performance

The mineral admixture is one of the indispensable materials for ordinary high-performance concrete. In this paper, the pure cement paste and cement paste replacing by mineral admixture were tested by cement mortar. The SEM analysis of pure cement paste and mineral admixture paste after curing period of 7 days and 28 days.From the picture of SEM after the period of 7 days and 28 days,the cement hydration mechanism was suspected.It could be used for explanating the physical performance and durability performance of the high perfromance concrete with mineral admixture.

A Three Dimensional Microstructure Sphere Model of Cement Hydration

2014 ◽  
Vol 900 ◽  
pp. 421-425
Author(s):  
Xiao Lin Qiu ◽  
Yi Ren Zhou ◽  
Lang Wu ◽  
Bin Lei
Keyword(s):  
Chemical Reaction ◽  
Cement Hydration ◽  
Diffusion Rate ◽  
Early Stage ◽  
Kinetic Equations ◽  
Three Dimensional ◽  
Characteristic Parameters ◽  
Sphere Model ◽  
Hydration Degree ◽  
Hydration Mechanism

A microstructure kinetic model is introduced for the hydration of cementitious materials.The hydration degree is mainly controlled by chemical reaction or diffusion rate in hydrate process of cement. According to evolution of characteristic parameters in two main processes, the hydrated kinetic equations is given in the paper. The kinetic equations can simulate the main hydrated processes, and an understanding on the hydration mechanism of cement can be emphasized. Chemical reaction dominates in the early stage of hydration, diffusion rate becomes the dominating factor gradually as the hydration degree increases.

Citric Acid on the Hydration Mechanism of Cement

2011 ◽  
Vol 413 ◽  
pp. 174-179
Author(s):  
Bao Guo Ma ◽  
Jun Xiao ◽  
Hong Bo Tan
Keyword(s):  
Citric Acid ◽  
Key Words ◽  
Cement Hydration ◽  
Hydration Heat ◽  
Hydration Process ◽  
Chemical Shrinkage ◽  
Early Hydration ◽  
Hydration Mechanism ◽  
Diffraction Peaks ◽  
Acid Dosage

This article reports on the study to evaluate the hydration process of cement by the addition of citric acid. Through the test of citric acid of cement paste, hydration heat performance, resistivity, chemical shrinkage, and combined with XRD, SEM, DSC-TG discusses the influence of citric acid on cement hydration process. The results thus obtained were compared to the hydration process of cement with the blank sample and vary of dosage of citric acid. The results show that: The early hydration about 1~2 h resistivity increases, dissolve balance stage was extended; The chemical shrinkage increased significantly, and increases with dosage; With the increase in citric acid dosage, AFt diffraction peaks increases, while the CH peak decreases, indicating that the citric acid accelerated the initial hydration of C3A, while inhibiting C3S hydration and promoting AFt generation. Key words: citric acid, mechanism ,hydration heat, resistivity

scholarly journals 1H NMR Spin-Lattice Relaxometry of Cement Pastes with Polycarboxylate Superplasticizers

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5626
Author(s):  
Min Pang ◽  
Zhenping Sun ◽  
Qi Li ◽  
Yanliang Ji
Keyword(s):  
Signal Intensity ◽  
Cement Hydration ◽  
Weighted Average ◽  
Main Peak ◽  
Cement Pastes ◽  
Total Signal ◽  
Spin Lattice ◽  
Hydration Mechanism ◽  
Highly Correlated ◽  
T1 Relaxometry

1H spin-lattice relaxometry (T1, longitudinal) of cement pastes with 0 to 0.18 wt % polycarboxylate superplasticizers (PCEs) at intervals of 0.06 wt % from 10 min to 1210 min was investigated. Results showed that the main peak in T1 relaxometry of cement pastes was shorter and lower along with the hydration times. PCEs delayed and lowered this main peak in T1 relaxometry of cement pastes at 10 min, 605 min and 1210 min, which was highly correlated to its dosages. In contrast, PCEs increased the total signal intensity of T1 of cement pastes at these three times, which still correlated to its dosages. Both changes of the main peak in T1 relaxometry and the total signal intensity of T1 revealed interferences on evaporable water during cement hydration by dispersion mechanisms of PCEs. The time-dependent evolution of weighted average T1 of cement pastes with different PCEs between 10 min and 1210 min was found regular to the four-stage hydration mechanism of tricalcium silicate.

scholarly journals A Novel Strength Model for Cement Marine Clay Based on the Mechanical-Chemical Coupling Behavior

2021 ◽  
Vol 9 (12) ◽  
pp. 1454
Author(s):  
Liyang Xu ◽  
Zihai Yan ◽  
Jiajia Yan ◽  
Qiliang Xu ◽  
Jiancai Zhu ◽  
...  
Keyword(s):  
Cement Hydration ◽  
Theoretical Perspective ◽  
Mechanical Parameters ◽  
Marine Clay ◽  
Porosity Level ◽  
Hydration Mechanism ◽  
Coupling Behavior ◽  
Strength Based ◽  
Chemical Coupling ◽  
Strength Models

Crucial mechanical-chemical (MC) interactions occur during the cement hydration process in cement marine clay; however, the role of such an important element of the resulting strength has been subject to less investigation, particularly from the theoretical perspective. To overcome this scientific gap, an efficient strength-based model accounting for the coupled MC processes is proposed here. Based on the analysis of the cement hydration mechanism, the porosity was chosen as the main factor to characterize the influence of the MC interactions on the overall response. To verify the accuracy of the MC model, the unconfined compressive strength (UCS) experiment was conducted for the cement marine clay samples, and the corresponding simulation model was constructed using COMSOL multiphysics®. In addition, a comparison between the predicted results by the existing three strength models and the proposed MC model was performed. Subsequently, the sensitivity analysis and identification of mechanical parameters were carefully carried out. The obtained results show that the UCS strength for Taizhou clay ranges from 10.21 kPa to 354.2 kPa as the cement content increases from 10% to 20%, and the curing time varies from 3 days to 28 days. The mechanical parameters in the MC model can be obtained according to the porosity level. A reasonably good agreement between the UCS strength results of simulations and the experimentally observed data is reported. Additionally, the predicted UCS strength results by the MC model demonstrate the best correspondence with the measured values, indicating the high efficacy of the established model.

Analysis of Portland Cement Hydration Mechanism and its Material Applications in Engineering

2012 ◽  
Vol 578 ◽  
pp. 121-124 ◽  
Author(s):  
Hong Liang Huang ◽  
Hui Fang Zhang ◽  
Fei Zhao ◽  
Xue Fei Li ◽  
Yan Fang Li
Keyword(s):  
Portland Cement ◽  
Quantitative Measurement ◽  
Cement Hydration ◽  
Ultrasonic Method ◽  
Combine Method ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Hydration Mechanism ◽  
Resistivity Method ◽  
Portland Cement Hydration

On the basis to clarify the Portland cement hydration mechanism, we have a brief analysis of research methods about Portland cement hydration mechanism, mainly including the hydration heat, ultrasonic method, resistivity method, mercury intrusion method, chemical combine method, CH quantitative measurement, X-ray diffraction method, scanning electron microscopy, providing a theoretical basis of Portland cement hydration mechanism and its material applications in engineering for further study and improvement.

Mechanism of Preferential Adsorption of Carboxylic-Vinyl Copolymer, Hydroxy Carboxylate and Sulfonation - Polyol in Cement Hydration Process

2011 ◽  
Vol 194-196 ◽  
pp. 1035-1040 ◽  
Author(s):  
Hong Bo Tan ◽  
Bao Guo Ma ◽  
Kai Ke ◽  
Jun Xiao
Keyword(s):  
Ternary System ◽  
Organic Compounds ◽  
Steric Hindrance ◽  
Cement Hydration ◽  
Xrd Analysis ◽  
Chemical Shrinkage ◽  
Hydration Products ◽  
Adsorption Model ◽  
Hydration Mechanism ◽  
Preferential Adsorption

In the ternary system of hydroxy carboxylate (HC), sulfonation-polyol (SP) and carboxylic-vinyl copolymer (PC), HC and SP preferentially adsorb on the surface of particles to shield the initial hydration. In this way, the ternary system has excellent dispersibility and holding dispersibility, and it has little effect on later hydration. By means of the chemical shrinkage, SEM and XRD analysis, the hydration mechanism of the hydroxy carboxylate (HC) and sulfonation-polyol (SP) has been discussed and the preferential adsorption model (PAM) has been established. The results show that HC delays the initial hydration of C3S and accelerates both the hydration of C3A and the formation of AFt; HC reduces the strength for 28 d with the addition of 0.2%; SP delays initial hydration of C3S and C3A; the ability of shielding hydration becomes weaker along with cement hydrating and the development of strength is normal. In the ternary system of HC, SP and PC, HC and SP with the electrostatic attraction of -SO3- and COO- and complexation of OH- preferentially adsorb on the surface of particles and active hydrating points. Then, reaction of active hydrating points was shielded and the growth of the hydration products slows. In this way, hydration of C3A and C3S are delayed, and the holding dispersibility of PC becomes better. The PC preferentially adsorbs on inert hydrating points and consumes slowly to provide dispersibility with steric hindrance. Along with hydrating going on, organic compounds are enwrapped by hydration products and the shielding ability becomes weaker and weaker. Then, the hydration becomes normal.

PRACTICAL PROCEDURES FOR INTENSIFYING CEMENT HYDRATION

2016 ◽  
Vol 15 (2) ◽  
pp. 307-314
Author(s):  
Vladimir Corobceanu ◽  
Ciprian Ilie Cozmanciuc ◽  
Razvan Giusca ◽  
Constantin Gavriloaia
Keyword(s):  
Cement Hydration
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