Surface properties of cement hydration products. I. Pore structure of calcium silicate hydrates prepared in a suspension form

2007 ◽  
Vol 19 (11) ◽  
pp. 324-328 ◽  
Author(s):  
R. Sh. Mikhail ◽  
A. M. Kamel ◽  
S. A. Abo-El-Enein
Keyword(s):  
Pore Structure ◽  
Surface Properties ◽  
Calcium Silicate ◽  
Cement Hydration ◽  
Hydration Products ◽  
Calcium Silicate Hydrates

Physical and Chemical Influence of Polyacrylate Latex on Cement Mortars

2011 ◽  
Vol 261-263 ◽  
pp. 807-811 ◽  
Author(s):  
Ye Tian ◽  
Zong Jin Li ◽  
Hong Yan Ma ◽  
Xian Yu Jin ◽  
Nan Guo Jin
Keyword(s):  
Pore Structure ◽  
Cement Hydration ◽  
Bending Strength ◽  
Mechanical Performance ◽  
Air Entrainment ◽  
Hydration Products ◽  
Cement Mortars ◽  
Cement Based Materials ◽  
Physical And Chemical ◽  
Chemical Influence

In this research, the physical and chemical influence of polyacrylate (PA) latex on cement-based materials were studied using polymer modified mortars with polymer/cement (P/C) ratios of 0%, 5% and 10%. Physically, the mechanical performance of PA latex modified mortars was investigated with compression toughness energy and bending strength. Further more, a comparison of the pore structure and porosity between PA latex modified and unmodified mortars was conducted. The chemical reactions between PA polymer and cement hydrates were clarified with thermogravimetric (TG) analysis. It can be concluded from this research that PA polymer can refine the pore structure of cement mortars and link the cement hydration products together chemically. While, at the same time, PA latex addition can cause air entrainment which will weaken the physical behavior of cement mortars. So there is an optimum P/C ratio to achieve the best mechanical properties. And in this research, the optimum P/C ratio is 5%.

scholarly journals Effect of Some Admixtures on the Surface Properties of the Hydration Products of Silica Fume/Ca(OH)2 Mixtures

2000 ◽  
Vol 18 (3) ◽  
pp. 195-204
Author(s):  
E.E. Hekal ◽  
N.A. Mousa
Keyword(s):  
Surface Properties ◽  
Silica Fume ◽  
Calcium Silicate ◽  
Spectroscopic Analysis ◽  
Gas Adsorption ◽  
Hydration Reaction ◽  
Physical Interaction ◽  
Nitrogen Gas ◽  
Calcium Silicate Hydrates ◽  
Ir Spectroscopic

The effect of sodium naphthalene formaldehyde sulphonate polycondensate and stearic acid on the surface properties of calcium silicate hydrates, formed as a result of the hydration reaction between silica fume and calcium hydroxide, has been examined by the use of low-temperature nitrogen gas adsorption techniques. In addition, the interaction of such admixtures with the calcium silicate hydrates formed was investigated by infrared (IR) spectroscopic analysis. It was observed that both admixtures increased the specific surface area of the calcium silicate hydrates quite considerably relative to the behaviour of a blank sample (i.e. without addition of admixture), especially during the initial stages of hydration (after 24 h). IR examination demonstrated that the admixtures used did not interact chemically with the calcium silicate hydrates although physical interaction was possible.

Experimental Researches on Microstructure of Nanometer Silicon and Cement-Stabilized Soils

2011 ◽  
Vol 94-96 ◽  
pp. 358-364 ◽  
Author(s):  
Li Feng Wang
Keyword(s):  
Compressive Strength ◽  
Calcium Silicate ◽  
Unconfined Compressive Strength ◽  
Silicon Powder ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcium Silicate Hydrates ◽  
Stabilized Soil ◽  
Experimental Researches

Unconfined compressive strength of various mixing proportions and ages of nanometer silicon and cement-stabilized soils（NCSS） are tested ,and the rules of compressive strength are got. Hydration products and microstructures of NCSS are discussed by means of XRD and SEM technology, and microstructural mechanisms of NCSS are analyzed. Results show that nanometer silicon powder added to cement-stabilized soil(CSS) can sharply improve the compressive strength of CSS. More Calcium silicate hydrates(C-S-H) and other hydration products can be produced in the process of secondary reaction of cement and water added nanometer silicon powder. X ray diffraction tests indicate the kinds and quantities of C-S-H increase with nanometer silicon contents. Strengths of NCSS are bettered by increasing jointed strength changed from edge-edge, edge-face connectios to cementation connections affected by increasing hydration products. Large pores of NCSS can be greatly decreased by adding nanometer silicon powder, and hydration products filling in the pores make NCSS more dense materials.

scholarly journals Creep of a C-S-H gel: a micromechanical approach

2010 ◽  
Vol 82 (1) ◽  
pp. 25-41 ◽  
Author(s):  
Julien Sanahuja ◽  
Luc Dormieux
Keyword(s):  
Strain Rate ◽  
Creep Behavior ◽  
Calcium Silicate ◽  
Elastic Strain ◽  
Hydration Products ◽  
Microscopic Mechanism ◽  
Calcium Silicate Hydrates ◽  
Micromechanical Approach ◽  
Short And Long Term

Both clays and calcium silicate hydrates(the main hydration products of Portland cements) exhibit a microstructure made up of lamellar particles. The microscopic mechanism responsible for the macroscopic creep of such materials is often described as the relative sliding of the sheets. This paper proposes a micromechanical approach to estimate the macroscopic creep behavior rising from this microscopic mechanism. The asymptotic evolution of creep at both short- and long-term is especially investigated. More precisely, a non-vanishing initial elastic strain is retrieved. At long-term, a threshold on porosity appears. At lower porosities, the creep evolution admits an asymptotic strain. At higher porosities, it admits an asymptotic strain rate.

scholarly journals Effect of C-S-H Nucleating Agent on Cement Hydration

2021 ◽  
Vol 11 (14) ◽  
pp. 6638
Author(s):  
Wenhao Zhao ◽  
Xuping Ji ◽  
Yaqing Jiang ◽  
Tinghong Pan
Keyword(s):  
Fractal Dimension ◽  
Cement Hydration ◽  
Nucleating Agent ◽  
Crystal Nucleation ◽  
Enhancement Effect ◽  
Hydration Products ◽  
Hydration Degree ◽  
Hydration Kinetics ◽  
Cement Mortars ◽  
Early Strength

This work aims to study the effect of a nucleating agent on cement hydration. Firstly, the C-S-H crystal nucleation early strength agent (CNA) is prepared. Then, the effects of CNA on cement hydration mechanism, early strength enhancement effect, C-S-H content, 28-days hydration degree and 28-days fractal dimension of hydration products are studied by hydration kinetics calculation, resistivity test, BET specific surface area test and quantitative analysis of backscattered electron (BSE) images, respectively. The results show that CNA significantly improves the hydration degree of cement mixture, which is better than triethanolamine (TEA). CNA shortens the beginning time of the induction period by 49.3 min and the end time of the cement hydration acceleration period by 105.1 min than the blank sample. CNA increases the fractal dimension of hydration products, while TEA decreases the fractal dimension. CNA significantly improves the early strength of cement mortars; the 1-day and 3-days strength of cement mortars with CNA are more than the 3-days and 7-days strength of the blank sample. These results will provide a reference for the practical application of the C-S-H nucleating agent.

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