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Abstract  

DTA/TG/DTG thermoanalytical investigation and X-ray diffractometry were carried out on hydraulic lime pastes obtained by mixtures of thermally activated red earth with lime. Hydration reactions proceed properly mostly due to the high silica and alumina content. In a long period of curing the paste presents calcium silicates hydrate in high quantities while there are moderate quantities of calcium monocarboaluminate hydrate, ettringite and gehelenite hydrated. In presence of chloride, pastes lead, after few days, a sensible acceleration of the hydration with the formation of calcium silicate hydrate and calcium chloroaluminate hydrate. The total amount of neo-formed hydrate products in the hardened paste, indicate a development of the solidifying/stabilizing capacity of the hydraulic binder.

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Abstract  

The properties of hydraulic mortars were studied by means of simultaneous thermal analysis (STA), according to a procedure proposed in the literature. Hydraulic limes, cement and/or slaked lime were mixed using different proportions of both inert and reactive aggregates, in order to test the effectiveness of such procedure in distinguishing the different degree of hydraulicity of such samples. The use of the normalized coordinates suggested in the literature results in overlapping of the clusters of different kinds of mortars. Modified coordinates are proposed, which give promising results in view of outlining a ‘master curve’ of hydraulicity.

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–3, 3–5 mm) and CAC as hydraulic binder (15 wt%). A spinel, MgO·Al 2 O 3 , was used as an additive in concrete mixture. A chemical composition of starting raw materials obtained by atomic absorption spectrophotometer, AAS Analyst 300, is given in Table

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Abstract  

The present research is concerning the characterization of FDR (fuel derived from residues) fly ash and mixtures with lime/brick hydraulic binder by DTA/TG/DTG thermo-analysis, X-ray diffractometry and chemical analysis. The use of hydraulic binder obtained from building brick rejects, which is less expensive than the usual solidifiers such as cementitious binder and silicates, allows us to reutilize, in the meantime, this wreckage material, to the advantage of environmental sustainability. Fly ash samples investigated in the present study were separated in a thermo-incineration plant. Mineralogical DTA/TG/DTG and XRD investigations reveal the presence of different phases as well as chemical analysis shows a moderate concentration of heavy metals and high content of chloride and sulphate. Results obtained from leaching tests with water carried out on hardened pastes containing fly ash lead to interesting results, which highlight behaviour to the release of contaminants. The whole of the results obtained in the present study make it possible to regard the objective of disposing such hardened materials in inert waste landfill sites as achievable.

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Introduction Calcium aluminate cements (CAC) are special hydraulic binders, especially used in refractory concretes. Castable refractories containing CAC are used in different furnaces lining applications in ceramic, cement

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-leveling screeds, tile adhesives, grouting mortars and rapid-hardening repair mortars, CAC is an essential part of the hydraulic binder. Additionally, it is well known that CAC is added into Portland cement (PC) to accelerate setting [ 2 – 5 ]. But, the replacement

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Introduction Calcium aluminate cements (CACs) are quickly hardening hydraulic binders, which significantly differ in their chemical and phase compositions, properties and applications from often used Portland cements. They

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Introduction Calcium aluminate cements are hydraulic binders of special properties and applications. They are mainly applied in production of fire-resistant materials but this kind of cement is also useful in cases when

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