PRACTICAL PROCEDURES FOR INTENSIFYING CEMENT HYDRATION

Background: Concrete is a common material used in the construction of marine structures, such as bridges, water treatment plants, jetties, etc. The use of concrete in these environment exposes it to attack from chemicals like sulphates, chlorides and alkaline, thereby causing it to deteriorate, and unable to perform satisfactorily within its service life. Hence, the need to investigate the durability properties of concrete has become necessary especially when admixtures are used to modify some of its properties. Objective: This research work investigates the effect of Cassava Starch (CS) on the durability characteristics of concrete. Methods: The durability properties investigated in this work are water absorption, sorptivity, resistance to sulphates, sodium hydroxides and chloride penetration. The specimens were prepared by adding CS by weight of cement at 0.4, 0.8, 1.2, 1.6 and 2.0% respectively. The concrete specimens were cured for 28 days, tested for compressive strength before ponding in ionic solutions of sodium hydroxide, sulphuric acid and sodium chloride. Six (6) concrete mixes were prepared, five of which were used to evaluate the effect of CS on the durability characteristics of concrete. Results: The slump values reduced with the increasing dosage of CS due to the viscous nature of the CS paste. Generally, the addition of CS in concrete tends to improve the resistance of concrete to sulphate and chloride attack due to the ability of the muddy-like starch gel to block the pore spaces of hardened concrete, hence, reduces the rate at which water and other aggressive chemicals penetrate the concrete. In addition, the retarding ability of CS impedes the formation of mono-sulphate aluminates during cement hydration, thereby making the concrete less susceptible to sulphate attack. Conclusion: The addition of CS to concrete by weight of cement generally improved the durability characteristics of concrete, while the relative performances of the concrete mixes showed that CS 2.0 gave a better resistance to chloride penetration and sulphate attack.

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A review on the properties, reinforcing effects, and commercialization of nanomaterials for cement-based materials

Nanotechnology Reviews ◽

10.1515/ntrev-2020-0023 ◽

2020 ◽

Vol 9 (1) ◽

pp. 303-322 ◽

Cited By ~ 3

Author(s):

Zhifang Zhao ◽

Tianqi Qi ◽

Wei Zhou ◽

David Hui ◽

Cong Xiao ◽

...

Keyword(s):

Cement Hydration ◽

State Of The Art ◽

Research Progress ◽

Market Survey ◽

Future Perspectives ◽

Nano Silica ◽

Physical Processes ◽

Existing Problems ◽

Cement Based Materials ◽

The Cost

AbstractThe behavior of cement-based materials is manipulated by chemical and physical processes at the nanolevel. Therefore, the application of nanomaterials in civil engineering to develop nano-modified cement-based materials is a promising research. In recent decades, a large number of researchers have tried to improve the properties of cement-based materials by employing various nanomaterials and to characterize the mechanism of nano-strengthening. In this study, the state of the art progress of nano-modified cement-based materials is systematically reviewed and summarized. First, this study reviews the basic properties and dispersion methods of nanomaterials commonly used in cement-based materials, including carbon nanotubes, carbon nanofibers, graphene, graphene oxide, nano-silica, nano-calcium carbonate, nano-calcium silicate hydrate, etc. Then the research progress on nano-engineered cementitious composites is reviewed from the view of accelerating cement hydration, reinforcing mechanical properties, and improving durability. In addition, the market and applications of nanomaterials for cement-based materials are briefly discussed, and the cost is creatively summarized through market survey. Finally, this study also summarizes the existing problems in current research and provides future perspectives accordingly.

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The impact of Fe dosage on the ettringite formation during high ferrite cement hydration

Journal of the American Ceramic Society ◽

10.1111/jace.17640 ◽

2020 ◽

Author(s):

Dawei Wan ◽

Wenqin Zhang ◽

Yong Tao ◽

Zonghua Wan ◽

Fazhou Wang ◽

...

Keyword(s):

Cement Hydration ◽

Ettringite Formation ◽

The Impact

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Effect of Morphologically Controlled Hematite Nanoparticles on the Properties of Fly Ash Blended Cement

Nanomaterials ◽

10.3390/nano11041003 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1003

Author(s):

Pantharee Kongsat ◽

Sakprayut Sinthupinyo ◽

Edgar A. O’Rear ◽

Thirawudh Pongprayoon

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Size Distribution ◽

Cement Hydration ◽

Blended Cement ◽

Spherical Shape ◽

Particle Sizes ◽

Fe2o3 Nanoparticles ◽

Structure And Properties ◽

Hematite Nanoparticles

Several types of hematite nanoparticles (α-Fe2O3) have been investigated for their effects on the structure and properties of fly ash (FA) blended cement. All synthesized nanoparticles were found to be of spherical shape, but of different particle sizes ranging from 10 to 195 nm depending on the surfactant used in their preparation. The cement hydration with time showed 1.0% α-Fe2O3 nanoparticles are effective accelerators for FA blended cement. Moreover, adding α-Fe2O3 nanoparticles in FA blended cement enhanced the compressive strength and workability of cement. Nanoparticle size and size distribution were important for optimal filling of various size of pores within the cement structure.

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Impact of limestone fineness on cement hydration at early age

Cement and Concrete Research ◽

10.1016/j.cemconres.2021.106515 ◽

2021 ◽

Vol 147 ◽

pp. 106515

Author(s):

Yosra Briki ◽

Maciej Zajac ◽

Mohsen Ben Haha ◽

Karen Scrivener

Keyword(s):

Cement Hydration ◽

Early Age

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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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