Effects of ground wollastonite on cement hydration kinetics and strength development

AbstractThis contribution investigates the effects of seawater and colloidal silica (NS) in the amounts of 1, 3 and 5 wt%, respectively, on the hydration, strength development and microstructural properties of Portland cement pastes. The data reveal that seawater has an accelerating effect on cement hydration and thus a significant contribution to early strength development was observed. The beneficial effect of seawater was reflected in an improvement in compressive strength for up to 14 days of hydration, while in the 28 days compressive strength values were comparable to that of cement pastes produced with demineralized water. The combination of seawater and NS significantly promotes cement hydration kinetics due to a synergistic effect, resulting in higher calcium hydroxide (CH) production. NS can thus react with the available CH through the pozzolanic reaction and produce more calcium silicate hydrate (C-S-H) gel. A noticeable improvement of strength development, as the result of the synergistic effect of NS and seawater, was therefore observed. In addition, mercury intrusion porosimetry (MIP) tests confirmed significant improvements in microstructure when NS and seawater were combined, resulting in the production of a more compact and dense hardened paste structure. The optimal amount of NS to be mixed with seawater, was found to be 3 wt% of cement.

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

Applied Sciences ◽

10.3390/app11146638 ◽

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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Reutilizing Waste Iron Tailing Powders as Filler in Mortar to Realize Cement Reduction and Strength Enhancement

Materials ◽

10.3390/ma15020541 ◽

2022 ◽

Vol 15 (2) ◽

pp. 541

Author(s):

Liyun Cui ◽

Peiyuan Chen ◽

Liang Wang ◽

Ying Xu ◽

Hao Wang

Keyword(s):

Cement Hydration ◽

Mercury Intrusion Porosimetry ◽

Economic Cost ◽

Strength Development ◽

Effective Utilization ◽

Strength Enhancement ◽

Nucleation Effect ◽

Practical Engineering ◽

Internal Mechanism ◽

Massive Accumulation

Recently, the massive accumulation of waste iron tailings powder (WITP) has resulted in significant environmental pollution. To solve this problem, this paper proposes an original mortar replacement (M) method to reuse waste solids and reduce cement consumption. In the experiment, the author employed an M method which replaces water, cement, and sand with WITP under constant water/cement and found that the strength development can be significantly improved. Specifically, a mortar with 20% WITP replacement can obtain a 30.95% improvement in strength development. To study the internal mechanism, we performed experiments such as thermogravimetric analysis (TGA), mercury intrusion porosimetry (MIP), and SEM. The results demonstrate that the nucleation effect and pozzolanic effect of WITP can help promote cement hydration, and MIP reveals that WITP can effectively optimize pore structure. In addition, 1 kg 20% WITP mortar reduced cement consumption by 20%, which saves 19.98% of the economic cost. Comprehensively, our approach achieves the effective utilization of WITP and provides a favorable reference for practical engineering.

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Effect of nano-SnO2 on early-age hydration of Portland cement paste

Advances in Mechanical Engineering ◽

10.1177/1687814019851946 ◽

2019 ◽

Vol 11 (6) ◽

pp. 168781401985194 ◽

Cited By ~ 4

Author(s):

Jianping Zhu ◽

Genshen Li ◽

Ruijie Xia ◽

Huanhuan Hou ◽

Haibin Yin ◽

...

Keyword(s):

Portland Cement ◽

Cement Paste ◽

Cement Hydration ◽

Cementitious Materials ◽

Hydration Process ◽

Strength Development ◽

Early Age ◽

Test Machine ◽

Portland Cement Paste ◽

Scanning Electron

Nanomaterial, as a new emerging material in the field of civil engineering, has been widely utilized to enhance the mechanical properties of cementitious material. Nano-SnO2 has presented high hardness characteristics, but there is little study of the application of nano-SnO2 in the cementitious materials. This study mainly investigated the hydration characteristics and strength development of Portland cement paste incorporating nano-SnO2 powders with 0%, 0.08%, and 0.20% dosage. It was found that the early-age compressive strength of cement paste could be greatly improved when nano-SnO2 was incorporated with 0.08% dosage. The hydration process and microstructure were then measured by hydraulic test machine, calorimeter, nanoindentation, X-ray diffraction, scanning electron microscope, and mercury intrusion porosimetry. It was found that the cement hydration process was promoted by the addition of nano-SnO2, and the total amount of heat released from cement hydration is also increased. In addition, the addition of nano-SnO2 can promote the generations of high density C-S-H and reduce the generations of low density C-S-H indicating the nucleation effect of nano-SnO2 in the crystal growth process. The porosity and probable pore diameter of cement paste with 0.08% nano-SnO2 were decreased, and the scanning electron microscopic results also show that the cement paste with 0.08% nano-SnO2 promotes the densification of cement microstructure, which are consistent with the strength performance.

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Differential calorimetry as a tool in the studies of cement hydration kinetics with sulphate and nitrate solutions

Journal of Thermal Analysis and Calorimetry ◽

10.1007/s10973-017-6378-1 ◽

2017 ◽

Vol 130 (1) ◽

pp. 249-259 ◽

Cited By ~ 5

Author(s):

Wiesława Nocuń-Wczelik

Keyword(s):

Cement Hydration ◽

Hydration Kinetics ◽

Nitrate Solutions

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Nanoseeds as modifiers of the cement hydration kinetics

Smart Nanoconcretes and Cement-Based Materials ◽

10.1016/b978-0-12-817854-6.00010-6 ◽

2020 ◽

pp. 257-269

Author(s):

Gilberto Artioli ◽

Giorgio Ferrari ◽

Maria Chiara Dalconi ◽

Luca Valentini

Keyword(s):

Cement Hydration ◽

Hydration Kinetics

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Cement Hydration Models Research Based on Composition Content of each Phase of Minerals

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.204-208.3639 ◽

2012 ◽

Vol 204-208 ◽

pp. 3639-3643

Author(s):

Chun Hua Rao ◽

Lang Wu ◽

Bin Lei

Keyword(s):

Cement Hydration ◽

Curing Temperature ◽

Kinetics Model ◽

Hydration Degree ◽

Hydration Kinetics ◽

Cement Ratio ◽

Water Cement Ratio ◽

Hydration Rate ◽

Chemical Phase ◽

Temperature Water

Abstract: Based on the cement hydration kinetics model proposed by R.Berliner, taking into account the factors such as each chemical phase of minerals, curing temperature, water-cement ratio, the final hydration degree and fineness of cement, a theoretical hydration kinetics equations was established in this paper. It can be used to predict the hydration rate and the change of hydration degree.

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The Pozzolanic Reaction of Silica Fume

MRS Proceedings ◽

10.1557/opl.2012.1539 ◽

2012 ◽

Vol 1488 ◽

Cited By ~ 2

Author(s):

Ole M. Jensen

Keyword(s):

Silica Fume ◽

High Performance ◽

Cement Hydration ◽

Theoretical Calculations ◽

Pozzolanic Reaction ◽

Interfacial Transition Zone ◽

Strength Development ◽

Micro Structure ◽

Cementitious Binder ◽

Portland Cement Hydration

ABSTRACTSilica fume is a very important supplementary cementitious binder in High-Performance and Ultra High-Performance Concretes. Through its pozzolanic reaction the silica fume densifies the concrete micro-structure, in particular it strengthens the paste-aggregate interfacial transition zone. In the present paper different aspects of the pozzolanic reaction of silica fume are investigated. These include chemical shrinkage, isothermal heat development and strength development. Key data for these are given and compared with theoretical calculations, and based on presented measurements the energy of activation of the pozzolanic reaction of silica fume is estimated. The results show that the pozzolanic reaction of silica fume has notable differences from Portland cement hydration.

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