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potable tap water conforming to IS: 456 – 2000 [ 22 ] was used in this study for producing and curing of cement mortar. For producing good workability and high flowability with less water powder ratio polycarboxylic based superplasticizer (SP) and

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compressive strength of cement mortars was also examined. This article is a continuation of our previously published studies [ 20 ] on cement pastes with described waste catalyst. Experimental Materials

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Abstract  

The thaumasite form of sulphate attack (TSA) concerns cements and concretes containing limestone and is attributed to the formation of thaumasite. This work deals with the confirmation of thaumasite formation in cement mortars. Three types of cement were examined: Portland cement and Portland limestone cement containing 15 and 30% mass/mass limestone. The specimens were cured at 5C, for 12 months, in a 1.8% MgSO4 solution. The formation of thaumasite was checked and confirmed by XRD, TG and SEM. It was concluded that mortars containing limestone suffer from TSA at low temperature. The combination of XRD, TG and SEM leads to the positive identification of thaumasite and resolves the well known problem of thaumasite and ettringite confusion.

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Abstract  

Thermal analysis was first used to investigate the pattern of dissociation of hydrated ordinary Portland cement. Portlandite (Ca(OH)2) decomposes at about 500C. This was confirmed by kinetic calculations. Thermal analysis was then performed to establish the effect of varying the cement content on the percent mass loss associated with the decomposition of Ca(OH)2 in cement mortar cured for 28 days. An increasing relation was obtained. Standard concrete cubes were then prepared with cement contents ranging from 200 to 450 kg m-3. The loss in mass on heating, up to 750C, of concrete samples cured for 28 days was then related to the cement content in concrete. The relation obtained was tested for concrete cubes of known cement content and found to be in better agreement than the results obtained by conventional chemical analysis. This method can be used for an approximate determination of the cement content in concrete.

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Abstract  

The use of thermal analysis in studying ancient mortars in English cathedrals is explained. Thermal analysis can be used to investigate both mortar and stone in dated structures. Analysis of ancient mortars show that though recarbonated, they remain soft, yielding to structural deformations. The use of hard (cement mortar) in modern renovation can result in micro-cracking in the stone and subsequent chemical attack from the atmosphere. Contrary to the literature, data developed in the present study suggests that most medieval mortars have reached a near total state of recarbonation.

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cement mortars, Cement and Concrete Research , Vol. 32, No. 11, 2002, pp. 1823–1830. Nocu-Wczelik W. Effect of waste aluminosilicate material on cement hydration and properties of

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and flexural strengths of steel slag blended cements a Compressive strength, b Flexural strength Durability of steel slag blended cement mortars Resistance against

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. [11] Oliveira P. , Luiz A. , Gomes C. , João P. ; Pedro M.S. The potentia, Pozzolanic activity of glass and red-clay ceramic waste cement mortar

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analysis relating it to the relative strength, keeping the cement mortars and pastes with 0, 5, 10 and 15% replacement of cement with MK and with a water/binder (w/b) ratio of 0.55. The removal of portlandite by pozzolanic reaction reached a maximum at

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Pollack Periodica
Authors: Mohammed S. A. Khedr, Mona F. Ali, Abdullah M. A. Kamel, and Manal A. A. El-Ghanam

cement mortar tiles: Three case studies , Engineering Failure Analysis , Vol. 34 , 2013 , pp. 102 – 114 . [2] Botting T. , Guidry , J

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