Research on the Hydration Mechanism of Portland Cement with Magnesium Slag

Magnesium slag is a kind of industrial waste during the silicothermic process for magnesium reduction which has potential hydration activity. By adding 20% to 50% of magnesium slag into Portland cement, the influence principle of the additive amount of magnesium slag on the pozzolanic activity is investigated through performance testing and hydration products analysis. During the early period of hydration process, the strength of pozzolanic effectiveness ratio weakens with the increasing additive amount of magnesium slag, while during the later period of hydration process with the additive amount of magnesium slag less than 40%, the strength of pozzolanic effectiveness ratio increases with increasing additive amount of magnesium slag. The activity index of magnesium slag increases with the increase of period and additive amount, and the strength brought by hydration of magnesium slag is a key source of the strength improvement of Portland cement with magnesium slag.

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Study on Hydration Mechanism of Phosphoaluminate Cement

Materials Science Forum ◽

10.4028/www.scientific.net/msf.675-677.701 ◽

2011 ◽

Vol 675-677 ◽

pp. 701-704

Author(s):

Peng Liu ◽

Zhi Wu Yu ◽

Ling Kun Chen ◽

Zhu Ding

Keyword(s):

Portland Cement ◽

Electrochemical Impedance ◽

High Strength ◽

Heat Evolution ◽

Hydration Products ◽

X Ray Diffraction ◽

Scanning Microscope ◽

Hydration Mechanism ◽

Calcium Phosphorus ◽

Electron Scanning Microscope

Phosphoaluminate cement (PAC) is a kind of new cementitious material which has many special properties compared to Portland cement (PC). PAC sets quickly and develops early-high strength. In order to investigate the hydration mechanism, the hydration products and microstructure of PAC were studied with x-ray diffraction (XRD), electron scanning microscope (SEM) and electrochemical impedance spectroscopy (EIS). Heat evolution of PAC was also measured. The results show that the hydration mechanism of PAC is different from Portland cement, which is caused by the special minerals including CxP, CA(P), phase L, and so on. The main hydration products of PAC are calcium phosphorus aluminates hydrate (C-A-P-H), calcium phosphate hydrate (C-P-H), aluminates hydrate (C-A-H), the corresponding hydration microcrystal as well as gels. Also, there is no calcium hydroxide produced during hydration. The hydration procedure of PAC is divided into four stages which are dissolution and induction, acceleration, deceleration, stabilization.

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Resistivity Study on Early Hydration Process of Phosphoaluminate Cementitious Material

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.79-82.95 ◽

2009 ◽

Vol 79-82 ◽

pp. 95-98 ◽

Cited By ~ 1

Author(s):

Ming Zhang ◽

Zhu Ding ◽

Feng Xing ◽

Peng Liu

Keyword(s):

Resistivity Measurement ◽

Heat Evolution ◽

Hydration Process ◽

Early Age ◽

Hydration Products ◽

Microstructure Formation ◽

Time Curve ◽

Early Hydration ◽

Hydration Mechanism ◽

Acceleration And Deceleration

An electrodeless resistivity measurement system developed recently can provide a reliable method for monitoring the hydration process of cement-based materials continuously and accurately. Phosphoaluminate cement (PAC) sets quickly and develops high early strength. In order to understand the mechanism, the hydration products and microstructure formation of PAC in early age need to be studied. In the study, early hydration process of PAC with different dosage of retarder was investigated by the electrodeless resistivity equipment. According to resistivity-time curve, resistivity of freshly mixed PAC paste decreases sharply and then rises slowly, some characteristic peaks appear at different hydration stages of PAC. Heat evolution of PAC was also measured. The hydration mechanism and structure formation were studied according to these results. Depending on the dosage of retarder, the hydration process of PAC includes four stages which are dissolution, induction, acceleration and deceleration.

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Study on Optimization Proportioning Experiment and its Hydration Mechanism of Composite Cementing Material

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.121-126.418 ◽

2011 ◽

Vol 121-126 ◽

pp. 418-422

Author(s):

Jin Xiao Liu ◽

Zeng De Yin ◽

Wen Bin Sun

Keyword(s):

Portland Cement ◽

Uniform Design ◽

Material Strength ◽

Filling Material ◽

Hydration Products ◽

Early Hydration ◽

Hydration Mechanism ◽

Cementing Material ◽

Aluminate Cement

This article aims at the accelerating characteristic of coal filling material. We scientifically made a series of proportion on composite-cementing material through uniform design with Portland cement, sulpho-aluminate cement and gypsums. After having testing the capability of this, we found that some certain composite-cementing material strength has been improved, both early and later strength. Furthermore, we also continually analyzed the hydration products and microstructure of composite-cementing material, then determined that early hydration products were mostly ettringites and later were C-S-H-centered and CH-centered gel.

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Effect of Admixture on Mechanical Behavior and Micro-Structure of Sulphoaluminate Composite Material

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.113-116.2193 ◽

2010 ◽

Vol 113-116 ◽

pp. 2193-2196

Author(s):

Ming Zhang ◽

Feng Xing ◽

De Cheng Zhang ◽

Yun Fei Zhang

Keyword(s):

Fly Ash ◽

Mechanical Behavior ◽

Early Period ◽

Diffraction Peak ◽

Strength Increase ◽

Hydration Products ◽

Micro Structure ◽

Early Hydration ◽

Hydration Mechanism ◽

Calcium Sulphoaluminate

Mechanical behavior of sulphoaluminate cement (SAC) mortar mixed slag (SL), fly ash (FA) and combined admixture were studied in the study, at the same time, hydration products and micro-structure were analyzed with XRD and SEM for making clear hydration mechanism. Test results show that early period strength of SAC mortar decreased, and strength contribution rate of admixture is combined admixture (slag + fly ash) ＞ slag ＞ fly ash on the same content due to the combined admixture is more beneficial to accelerate hydration. Yet strength increase of SAC mortar mixed admixture after cured 60d is not obvious, which was not large different with pure SAC mortar. A large amount of ettringite and gel produced during 1d period of SAC paste, but with the hydration carrying on, diffraction peak of hydration products (ettringite and gel) and unhydrated calcium sulphoaluminate change little, which means hydration degree at 1d is higher. Diffraction peak of ettringite and gel at different curing period is lower when mixed admixture in matrix, the amount of ettringite and gel increased and unhydrated calcium sulphoaluminate decreased with hydration carrying on, which means early hydration speed slow down when introduction of admixture into SAC matrix.

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Research on the Properties of Composite Portland Cement with High Volume of Industry Waste

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.575-576.319 ◽

2013 ◽

Vol 575-576 ◽

pp. 319-322

Author(s):

Bao Li Du ◽

Xing Hua Fu ◽

Wen Hong Tao ◽

Xin Jin

Keyword(s):

Portland Cement ◽

High Volume ◽

Optimum Combination ◽

National Standard ◽

Hydration Products ◽

Industry Waste ◽

Hydration Mechanism ◽

Orthogonal Experiments ◽

Cement Mixture ◽

Cement Strength

The paper studied the influences of some industry wastes on the properties of composite Portland cement. Different amount of wastes were added as cement mixture. Through the investigation of properties of cement by orthogonal experiments, the optimum combination was obtained. The hydration products were analyzed by XRD and SEM. Its hydration mechanism was investigated and the result shows that with appropriate ration of each influencing factors, the cement could meet the national standard 42.5MPa of cement strength.

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Analysis of Hydration Mechanism of New Type Filling Cementitious Materials

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.753-755.814 ◽

2013 ◽

Vol 753-755 ◽

pp. 814-818 ◽

Cited By ~ 2

Author(s):

Shi Qing Nan ◽

Qian Gao ◽

Juan Xia Zhang ◽

Xian Zhang Guo

Keyword(s):

Influence Factor ◽

Cementitious Materials ◽

Cementitious Material ◽

Microstructure Analysis ◽

Hydration Process ◽

Hydration Products ◽

Hydration Mechanism ◽

Xrd Diffraction ◽

New Type

This paper mainly focuses on revealing the hydration mechanism of new cementitious material of filling body through its microstructure analysis. According to the SEM samples preparation, analysis of different age of filling body microstructure and XRD diffraction mapping, the results showed that the hydration products were with large amount of ettringite, followed by C-S-H gel, calcium and silica. The main reason of strength increasing was the ettringite morphology and the hydration process. It was obtained that the hydration products of different activators were mainly the influence factor of strength, on basis of analyzing the microstructure of different activator materials.

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Component Modification of Basic Oxygen Furnace Slag with C4AF as Target Mineral and Application

Sustainability ◽

10.3390/su13126536 ◽

2021 ◽

Vol 13 (12) ◽

pp. 6536

Author(s):

Yanrong Zhao ◽

Pengliang Sun ◽

Ping Chen ◽

Xiaomin Guan ◽

Yuanhao Wang ◽

...

Keyword(s):

Intermediate Phase ◽

Raw Materials ◽

Activity Index ◽

Basic Oxygen Furnace ◽

Hydration Products ◽

Basic Oxygen ◽

Bof Slag ◽

Mineral Compositions ◽

Slag Component ◽

Basic Oxygen Furnace Slag

In this paper, a new method of basic oxygen furnace (BOF) slag component modification with a regulator was studied. The main mineral was designed as C4AF, C2S and C3S in modified BOF slag, and the batching method, mineral compositions, hydration rate, activation index and capability of resisting sulfate corrode also were studied. XRD, BEI and EDS were used to characterize the mineral formation, and SEM was used to study the morphology of hydration products. The results show that most inert phase in BOF slag can be converted into active minerals of C4AF and C2S through reasonable batching calculation and the amount of regulating agent. The formation of C4AF and C2S in modified BOF slag is better, and a small amount of MgO is embedded in the white intermediate phase, but C3S is not detected. With the increase in the CaO/SiO2 ratio in raw materials, the CaO/SiO2 ratio of calcium silicate minerals in modified BOF slag increases, the contents of f-CaO are less than 1.0%, and the activity index improves. Compared with the BOF slag, the activity index and exothermic rate of modified BOF slag improved obviously, and the activity index of 90 days is close to 100%. With the increase in modified BOF slag B cement, the flexural strength decrease; however, the capability of resisting sulfate corrode is improved due to the constant formation of a short rod-like shape ettringite in Na2SO4 solution and the improvement of the structure densification of the hydration products.

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Using of Microsilica for Strength Improvement of Fiber Reinforced Cementitious Surface Compounds

ISRN Materials Science ◽

10.1155/2013/173587 ◽

2013 ◽

Vol 2013 ◽

pp. 1-7

Author(s):

S. S. Shebl ◽

Ibrahim S. Khalil ◽

H. Shoukry

Keyword(s):

Date Palm ◽

Fine Sand ◽

Structural Performance ◽

Polypropylene Fibers ◽

Hydration Products ◽

Fiber Reinforced ◽

Surface Compounds ◽

Extension Work ◽

Strength Improvement

This study represents an extension work to investigate the role of ultra fine sand (UFS) in enhancing the mechanical properties of fiber reinforced cementitious compounds. The micro-structural origins were identified by scanning electron microscope (SEM). About 50% of UFS had a diameter of less than 20 μm. Ordinary Portland Cement (OPC) was partially substituted by UFS at 3, 5, 7 and 10% by weight of binder. It was found that as UFS loadings increase, the flexural, compressive, and tensile strengths increased up to about 5% UFS loading by 12.9, 15.7 and 30.1%, respectively, thereafter, a decrease in these properties was observed. This can be attributed to the pozzolanic effect besides the filling effect of UFS resulting in enhancing the interfacial bonds between the sand grains and hydration products that makes the paste more homogeneous and dense. The effect of both short natural and artificial fiber loadings on the structural performance of compounds was also studied. Loadings of 2%, by weight, of short natural date palm leaves’ midribs fibers (DP) and artificial polypropylene fibers (PP) were added to the 5% UFS blended mix. An increase in both flexural and tensile strength was achieved, while a decrease in the compressive strength was observed.

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Research Progress on the Hydration of Portland Cement with Calcined Clay and Limestone

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1036.240 ◽

2021 ◽

Vol 1036 ◽

pp. 240-246

Author(s):

Jin Tang ◽

Su Hua Ma ◽

Wei Feng Li ◽

Hui Yang ◽

Xiao Dong Shen

Keyword(s):

Mechanical Properties ◽

Portland Cement ◽

Cementitious Materials ◽

Supplementary Cementitious Materials ◽

Research Progress ◽

Hydration Reaction ◽

Hydration Products ◽

Early Hydration ◽

Calcined Clay ◽

Dense Microstructure

The use of calcined clay and limestone as supplementary cementitious materials, can have a certain influence on the hydration of Portland cement. This paper reviewed the influence of limestone and calcined clay and the mixture of limestone and calcined clay on the hydration of cement. Both limestone and calcined clay accelerate the hydration reaction in the early hydration age and enhance the properties of cement. Limestone reacts with C3A to form carboaluminate, which indirectly stabilized the presence of ettringite, while calcined clay consumed portlandite to form C-(A)-S-H gel, additional hydration products promote the densification of pore structure and increase the mechanical properties. The synergistic effect of calcined clay and limestone stabilize the existence of ettringite and stimulate the further formation of carboaluminate, as well as the C-(A)-S-H gel, contributed to a dense microstructure.

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