scholarly journals Study of the Effects of the Addition of Fly Ash from Carwash Sludge in Lime and Cement Pastes

2020 ◽  
Vol 12 (16) ◽  
pp. 6451
Author(s):  
María C. Rodríguez-Fernández ◽  
Juan D. Alonso ◽  
Carolina Montero ◽  
Juan F. Saldarriaga
Keyword(s):  
Compressive Strength ◽  
Wastewater Treatment ◽  
Fly Ash ◽  
Calcium Silicate ◽  
Calcium Silicate Hydrate ◽  
Wastewater Treatment Plants ◽  
Strength Properties ◽  
Cement Pastes ◽  
Cement Mortars ◽  
Sludge Waste

Sludge from carwash wastewater treatment plants has been evaluated as substitute for lime paste, as well as its behavior in cement mortars. Dry sludge waste was used with (CSlud) and without (USlud) pretreatment and have been characterized. The pastes were prepared with weight replacement of 5, 10, 15, and 20% of sludge. The formation of calcium silicate hydrate was determined by TGA, both in lime and cement pastes. The compressive strength properties were evaluated in mortars. It was found the mixtures which present the best results were those of 5 and 10% for USlud, and 10 and 20% for CSlud.

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 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.

scholarly journals Study on modification mechanism of workability and mechanical properties for graphene oxide-reinforced cement composite

2020 ◽  
Vol 10 ◽  
pp. 184798042091260
Author(s):  
Yuxia Suo ◽  
Rongxin Guo ◽  
Haiting Xia ◽  
Yang Yang ◽  
Feng Yan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Graphene Oxide ◽  
Calcium Hydroxide ◽  
Calcium Silicate ◽  
Calcium Silicate Hydrate ◽  
Inverse Correlation ◽  
Cement Composite ◽  
Hydration Reaction ◽  
Cement Pastes

Graphene oxide/cement composite was prepared using a graphene oxide aqueous solution. The workability and mechanical properties of graphene oxide/cement composite with different concentrations for graphene oxide and the ratio of water to cement were investigated. The results observed were the fluidity of cement pastes decreased noticeably with the addition of graphene oxide and increased with the increase in the ratio of water to cement for all tested samples of different graphene oxide contents. It is indicated that a noticeable inverse correlation between the concentration of graphene oxide and fluidity was observed, and a positive linear relationship between the ratio of water to cement and fluidity was also obtained. The compressive strength of cement pastes significantly improved in the presence of an appropriate concentration of graphene oxide as compared to that of the cement paste without graphene oxide; this difference was due to the denser microstructure of graphene oxide/cement composite than that of the control specimens. With the combined analysis of X-ray diffraction and scanning electron microscopy with energy-dispersive spectrometry, the results showed that graphene oxide could promote and regulate the formation and connection of calcium hydroxide and calcium silicate hydrate during the hydration reaction, forming numerous regular and extremely compact plate-shaped crystals, and the compact plate-shaped microstructures constituted of not only calcium hydroxide and calcium silicate hydrate but also wrapped ettringite. This investigation will provide a flexible way to preparation of graphene oxide/cement composite with wanted fluidity and optimized compressive strength that promote the industry application of graphene oxide/cement composite.

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.

scholarly journals Hydration study of mechanically activated mixtures of Portland cement and fly ash

2007 ◽  
Vol 72 (6) ◽  
pp. 591-604 ◽  
Author(s):  
Gordana Stefanovic ◽  
Ljubica Cojbasic ◽  
Zivko Sekulic ◽  
Srdjan Matijasevic
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Mechanical Activation ◽  
Early Period ◽  
Negative Effects ◽  
Early Hydration ◽  
Cement Pastes ◽  
Dta And Tg ◽  
Low Activity

Fly ash (FA) can be used in cement mixtures with certain limitations. The problem of the mentioned mixtures lies in the insufficient activity of the particles of FA in the reactions which are important for the establishment of the mechanical characteristics of cement. This is particularly true for the hydration reactions. As a result of this, cement pastes formed by mixing ash and clinker have worse characteristics compared to those of pure Portland cement (PC), especially in the early period of setting. As is well known, FA can be a good solution for the neutralization of the negative effects generated due to the creation of free Ca(OH)2 during the hydration of PC, provided that the problems with the low activity of FAare overcome. For the experiments in this study, a mixture of Portland cement and fly ash was used, the content of ash in the mixture being 30 % and 50 %. Mechanical activation was performed in a vibrating ring mill. The goal of this study was to demonstrate, through experimental results, that during the mechanical activation of a PC and FA mixture, the components in the mixture which mostly affect the direction, rate and range of hydration reactions occurring in the mixture had been activated. The values of the compressive strength of the activated and non-activated mixtures and the changes of their specific surface area proved that during the grinding process, the mixture PC+FA had been mechanically activated. The highest increase of compressive strength was achieved in the early period of setting, which indicates an improvement in the early hydration of the mixture. XRD, DTA and TG analyses showed that the alite (C3S) and belite (C2S) from the PC and a part of the fly ash were activated. .

High Volume Slag and Slag-Fly Ash Blended Cement Pastes Containing Nano Silica

2019 ◽  
Vol 967 ◽  
pp. 205-213
Author(s):  
Faiz U.A. Shaikh ◽  
Anwar Hosan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Cement Paste ◽  
Ordinary Portland Cement ◽  
Blended Cement ◽  
High Volume ◽  
Ash Content ◽  
Partial Replacement ◽  
Nano Silica ◽  
Cement Pastes

This paper presents the effect of nanosilica (NS) on compressive strength and microstructure of cement paste containing high volume slag and high volume slag-fly ash blend as partial replacement of ordinary Portland cement (OPC). Results show that high volume slag (HVS) cement paste containing 60% slag exhibited about 4% higher compressive strength than control cement paste, while the HVS cement paste containing 70% slag maintained the similar compressive strength to control cement paste. However, about 9% and 37% reduction in compressive strength in HVS cement pastes is observed due to use of 80% and 90% slag, respectively. The high volume slag-fly ash (HVSFA) cement pastes containing total slag and fly ash content of 60% exhibited about 5%-16% higher compressive strength than control cement paste. However, significant reduction in compressive strength is observed in higher slag-fly ash blends with increasing in fly ash contents. Results also show that the addition of 1-4% NS improves the compressive strength of HVS cement paste containing 70% slag by about 9-24%. However, at higher slag contents of 80% and 90% this improvement is even higher e.g. 11-29% and 17-41%, respectively. The NS addition also improves the compressive strength by about 1-59% and 5-21% in high volume slag-fly ash cement pastes containing 21% fly ash+49%slag and 24% fly ash+56%slag, respectively. The thermogravimetric analysis (TGA) results confirm the reduction of calcium hydroxide (CH) in HVS/HVSFA pastes containing NS indicating the formation of additional calcium silicate hydrate (CSH) gels in the system. By combining slag, fly ash and NS in high volumes e.g. 70-80%, the carbon footprint of cement paste is reduced by 66-76% while maintains the similar compressive strength of control cement paste. Keywords: high volume slag, nanosilica, compressive strength, TGA, high volume slag-fly ash blend, CO2 emission.

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