scholarly journals Effect of nano silica (SiO2) on the hydration kinetics of cement

2019 ◽  
Vol 39 (3) ◽  
pp. 248-260 ◽  
Author(s):  
Taher Abu-Lebdeh ◽  
Relly Victoria Virgil Petrescu ◽  
Moayyad Al-Nasra ◽  
Florian Ion Tiberiu Petrescu
Keyword(s):  
Compressive Strength ◽  
Calcium Silicate ◽  
Calcium Silicate Hydrate ◽  
Hydration Process ◽  
Strength Development ◽  
Hardened Cement ◽  
Nano Silica ◽  
Hydration Kinetics ◽  
Drastic Increase ◽  
Curing Method

This study investigated the influence of adding nano silica (SiO2) on the cement hydration process, particularly on the formation of calcium silicate hydrate (C-S-H) at different stages of hydration. The study investigated the effect of adding nano-silica on the mechanical properties of the hardened cement corresponding to the formation of C-S-H during the hydration process of a cement paste. Specimens made up of four different percentage of nano silica (0%, 1%, 3% and 5%) were tested at different stages of hydration ranging from 3 to 56 days. The effect of nano-silica on the compressive strength, stressstrain, and elastic modulus of nano-cement was examined using MTS and Forney testing machines. The signature phase and formation of C-S-H and calcium hydroxide (CH) were monitored using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The study also investigated the effect of curing method (vacuum and water curing) on the strength development. The experimental results show that the formation of calcium silicate hydrate (C-S-H) increases significantly during the early stages of hydration which correspond to the drastic increase in compressive strength. The formation of C-S-H continues to increase throughout the 56 days but at a moderate rate. The results reveal that 1% of nano silica by volume of cement is the optimum ratio that yields the maximum strength. The results also indicated that the strength of the traditional water cured specimens were higher than that of vacuum cured specimens.

INVESTIGATING THE EFFECT OF NANO SILICA ON THE MECHANICAL PROPERTIES OF HARDENED CEMENT PASTE

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Sameer Hamoush ◽  
Miguel Picornell ◽  
Taher Abu-Lebdeh
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Silica Content ◽  
Hydration Process ◽  
Hardened Cement ◽  
Nano Silica ◽  
Hardened Cement Paste ◽  
Cement Replacement ◽  
Water Curing ◽  
Curing Method

This study investigated the compressive strength of hardened cement paste and the formation of calcium silicate hydrate (C-S-H) with the addition of nano silica (SiO2). Through this search, the development of the concretes strength was determined to better understand the process of cement hydration. Compressive strength testing was performed using MTS and Forney testing machines to determine stress-strain curves and elastic modulus of materials. The hydration process and formation of C-S-H and calcium hydroxide (CH) was examined using Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). This study also incorporates the use of vacuum curing, in comparison to that of the traditional water curing method. Results indicate an increase in compressive strength using 1%, 3% and 5% of nano silica to cement replacement by volume in comparison to the control mix (without nano silica). The optimum cement replacement to yield maximum strength was of the 1% nano silica content. The formation of C-S-H increases significantly during the early testing days which correspond with the drastic increase in compressive strength. The hydration process continues to increase throughout the 56 day trails at a moderate rate. The traditional water curing method proves to be more efficient and beneficial than of the vacuum curing method. However, vacuum cured results showed only about a 5% reduction in strength after 56 day tests in comparison to the water curing method.

scholarly journals Autoclave-free ultra-early strength concrete preparation using an early strength agent and microstructure properties

RSC Advances ◽  
2021 ◽  
Vol 11 (28) ◽  
pp. 17369-17376
Author(s):  
Daosheng Sun ◽  
Ziwen Wang ◽  
Rui Ma ◽  
Aiguo Wang ◽  
Gaozhan Zhang
Keyword(s):  
Compressive Strength ◽  
Calcium Silicate ◽  
Calcium Silicate Hydrate ◽  
Strength Concrete ◽  
Compressive Strength Of Concrete ◽  
Early Strength

In this study, nano calcium silicate hydrate was used as an early strength agent to promote the compressive strength of concrete at 1 day.

scholarly journals Influence of the Ca/Si ratio on the compressive strength of cementitious calcium–silicate–hydrate binders

2017 ◽  
Vol 5 (33) ◽  
pp. 17401-17412 ◽  
Author(s):  
Wolfgang Kunther ◽  
Sergio Ferreiro ◽  
Jørgen Skibsted
Keyword(s):  
Compressive Strength ◽  
Calcium Silicate ◽  
Calcium Silicate Hydrate

Calcium–silicate–hydrate phases have been synthesized with Ca/Si ratios of 0.83–1.50 and it is demonstrated that the compressive strengths of the C–S–H pastes increase for decreasing Ca/Si ratio for all samples and testing ages.

Hydration Activity of Ceramic Polishing Powder at Autoclaved Condition

2012 ◽  
Vol 568 ◽  
pp. 392-395
Author(s):  
Ming Feng Zhong ◽  
Da Gen Su ◽  
Yi Xiang Zhao
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Calcium Silicate ◽  
Calcium Silicate Hydrate ◽  
Civil Engineering

Hydration activity of waste ceramic polishing powder at autocalved condition were studied by IR, XRD, SEM and EDS in civil engineering. The results shown that autoclaved condition is beneficial to inspire hydration ability of polishing powder, the more active silicon and aluminium were dissolved, and they were converted into low Ca/Si ratio calcium silicate hydrate, whose ratio of Ca/Si was 1.58, and the compressive strength of autoclaved silicate product made by the ceramic polishing powder was higher than that of fly ash.

scholarly journals The Influence of Superabsorbent Polymers and Nanosilica on the Hydration Process and Microstructure of Cementitious Mixtures

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5194
Author(s):  
Gerlinde Lefever ◽  
Dimitrios G. Aggelis ◽  
Nele De Belie ◽  
Marc Raes ◽  
Tom Hauffman ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Isothermal Calorimetry ◽  
Autogenous Shrinkage ◽  
Hydration Process ◽  
Microstructural Development ◽  
Self Healing ◽  
Hydration Kinetics ◽  
Superabsorbent Polymers ◽  
Water To Cement Ratio ◽  
Supplementary Material

Superabsorbent polymers (SAPs) are known to mitigate the development of autogenous shrinkage in cementitious mixtures with a low water-to-cement ratio. Moreover, the addition of SAPs promotes the self-healing ability of cracks. A drawback of using SAPs lies in the formation of macropores when the polymers release their absorbed water, leading to a reduction of the mechanical properties. Therefore, a supplementary material was introduced together with SAPs, being nanosilica, in order to obtain an identical compressive strength with respect to the reference material without additives. The exact cause of the similar compressive behaviour lies in the modification of the hydration process and subsequent microstructural development by both SAPs and nanosilica. Within the present study, the effect of SAPs and nanosilica on the hydration progress and the hardened properties is assessed. By means of isothermal calorimetry, the hydration kinetics were monitored. Subsequently, the quantity of hydration products formed was determined by thermogravimetric analysis and scanning electron microscopy, revealing an increased amount of hydrates for both SAP and nanosilica blends. An assessment of the pore size distribution was made using mercury intrusion porosimetry and demonstrated the increased porosity for SAP mixtures. A correlation between microstructure and the compressive strength displayed its influence on the mechanical behaviour.

scholarly journals Influence of Mortar Incorporating Silica Based Waste Material on the Formation of C-S-H and Mechanical Strength Properties

2014 ◽  
Vol 695 ◽  
pp. 647-650 ◽  
Author(s):  
Nafisa Tamanna ◽  
Norsuzailina Mohamed Sutan ◽  
Ibrahim Yakub ◽  
Delsye Teo Ching Lee ◽  
Ezzaq Farhan Ahmad
Keyword(s):  
Compressive Strength ◽  
Calcium Silicate ◽  
Calcium Silicate Hydrate ◽  
Glass Powder ◽  
Strength Properties ◽  
Particle Sizes ◽  
Replacement Level ◽  
Cement Ratio ◽  
Water To Cement Ratio ◽  
Partial Cement Replacement

Recent studies have been carried out to utilize waste glass in construction as partial cement replacement. This paper investigates the formation of Calcium Silicate Hydrate (C-S-H) and strength characteristics of mortar in which cement is partially replaced with glass powder by replacement level of 10%, 20% and 30%. Mortar cubes containing varying particle sizes in the ranges of 150-75μm, 63-38 μm and lower than 38 μm and in a water to cement ratio of 0.45 and 0.40 have been prepared. Replacement by 10% cement with glass powder reveals high compressive strength and produces more C-S-H at 28 days than other levels of replacement.

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