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Cement

About: Cement is a research topic. Over the lifetime, 68440 publications have been published within this topic receiving 829356 citations.


Papers
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Journal ArticleDOI
TL;DR: In this article, the authors present data on the durability of a new type of concrete incorporating high volumes of low-calcium (ASTM Class F) fly ash, which has excellent durability with regard to frost action, has low permeability to chloride ions and shows no adverse expansion when highly reactive aggregates are incorporated into the concrete.
Abstract: Research on structural concrete incorporating high volumes of low-calcium (ASTM Class F) fly ash has been in progress at CANMET since 1985. In this type of concrete, the cement content is kept at about 150 kg/m3. The water-to-cementitious materials ratio is of the order of 0·30, and fly ash varies from 54 to 58% of the total cementitious material. A large dosage of a superplasticizer is used to achieve high workability. This paper presents data on the durability of this new type of concrete. The durability aspects considered are: freezing and thawing cycling; resistance to chloride ion permeability; and the expansion of concrete specimens when highly reactive aggregates are used in the concrete. The investigations performed at CANMET indicate that concrete incorporating high volumes of low-calcium fly ash has excellent durability with regard to frost action, has very low permeability to chloride ions and shows no adverse expansion when highly reactive aggregates are incorporated into the concrete.

164 citations

Journal ArticleDOI
TL;DR: In this paper, waste oyster shells (WOS) were used as controlled low-strength materials (CLSM) to replace fine aggregate in cement mortar, and the hardened properties and the durability were tested.

164 citations

Journal ArticleDOI
TL;DR: In this paper, isothermal conduction calorimetry was used to explore hydration kinetics during the first 72h in a cement containing 30% OPC and 70% fly ash.
Abstract: Activated blends of Portland cement and fly ash with a high ash content (>70%) are a new alternative to traditional OPCs. A number of papers have been published on C–S–H and N–A–S–H, the two gels that constitute the main cementitious products generated by the alkaline activation of these cements, and the elements that may be taken up into their structure. Very little is known about the kinetics of these systems, however, particularly during the early stages of the reaction. The present study used isothermal conduction calorimetry to explore hydration kinetics during the first 72 h in a cement containing 30% OPC and 70% fly ash. Two activating solutions were used: a mix of NaOH + Na 2 SiO 3 and a Na 2 CO 3 solution. The findings showed that hydration kinetics were substantially modified by the type of alkaline activator used, particularly with respect to the secondary phases generated. In both cases the main reaction product appeared to be a mix of C–A–S–H and (N,C)–A–S–H gels, whose proportions were clearly impacted by the type of activator used.

164 citations

Journal ArticleDOI
TL;DR: In this article, the authors studied the environmental benefits of incorporating different percentages of two types of fly ashes that can be used in concrete as cement replacement, and they showed that both ashes provide a benefit for the concrete production both in terms of environmental impact minimization and a better environmental performance through an increase in cement replacement.

164 citations

Journal ArticleDOI
TL;DR: In this paper, the early age mechanical response of the cement mortar modified with graphene oxide using atomic force microscopy (AFM) was investigated by Infrared, Raman, X-ray diffraction (XRD) techniques.

164 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20248
20234,852
20228,607
20213,442
20203,929
20194,260