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the cement mortar that determines the specific properties of this concrete [ 1 ]. The composition of the self-compacting cement mortar (SCM) is characterized with (i) a large diversity of water-reducing admixtures, (ii) a high content of

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Pozzolanic reaction simply consists of an acid–base reaction between calcium hydroxide (Ca(OH) 2 ), and silicic acid (H 4 SiO 4 , or Si(OH) 4 ). The reactivity of pozzolans, in the case of lime-based mortars, is attributed to their content in amorphous silica

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Introduction The decorative cement mortars and concretes are an artificial imitation of the natural stones. The main advantage of these artificial stones is their better workability, but the durability and stability are their

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Abstract  

Roman ancient mortars have been widely studied, in connection with both diagnosis and application required for restoring. Thermoanalytical experiments performed on mortars from Pompeii and Herculaneum provided a very good understanding of the technology employed. The mortars from Pompeii were obtained by the proper mixing of lime and marble grains while mortars of Herculaneum by lime and silicates compounds. The position of the endothermic peak of calcite decomposition showed important variations in the different samples studied, which was assigned to the different crystallinity and particle sizes. Experiments under CO2 flow confirmed the presence of magnesium calcium carbonates.

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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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Abstract  

The ancient mortars of the monastery of San Filippo di Fragalà in Frazzanò, the first Basilian-Norman center in Sicily, have been studied and classified by means of ICP, HPLC, TG-DTA, XRD and thin sections analysis. A new very simple method to evaluate the hydraulic properties of the mortars, based on the combination of analytical and thermogravimetric data, is also reported. The HPLC investigations indicate that the monastery is only partially involved in decay phenomena due to the action of soluble salts.

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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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Abstract  

Two types of raw materials, original kaolin sand OKS I and OKS II were used for experiment. They were transformed (1 h at 650 °C with 10 °C/min temperature increase) to burnt kaolin sand (BKS I and BKS II) with pozzolanic properties. Contents of decisive mineral—metakaolinite—in BKSs are as follows: BKS I (fraction below 0.06 mm) 20%; BKS II (fraction below 0.06 mm) 36% and BKS II (fraction below 0.1 mm) 31% by mass. Mortars with blends of Portland cement (PC) and BKS were prepared announced as: MK I (0.06) with 5 and 10% cement substitution by metakaolinite; MK II (0.06) with 5 and 10% cement substitution by metakaolinite and MK II (0.1) with 5, 10, 15 and 20% cement substitution by metakaolinite. The reference mortar with 100% of PC was made for comparison. All mortars were adjusted on the constant workability 180 ± 5 mm flow. Besides significant increase in compressive strengths—the refinement of pore structure in mortars with BKS connected with decreases in permeability and Ca(OH)2 content were revealed. The above facts confirm pozzolanic reaction of BKS in contact with hydrated PC and indicate perceptiveness of BKS for the use in cement-based systems as a pozzolanic addition.

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Abstract  

This work presents the relation between the pozzolanic activity, the hydration heat and the compressive strength developed by blended mortars containing 10 and 35% of a spent fluid catalytic cracking catalyst (FCC). The results show that, in comparison with 100% Portland cement mortar, a mortar with 10% FCC increases the hydration heat all over the period of testing. This hydration heat increasing is due to the pozzolanic effect, therefore the resulting compressive strength is higher than the reference mortar. Whereas, in a mortar with 35% of FCC, the hydration heat is higher than 100% PC mortar, until 10 h of testing. After this age, the substitution degree predominates over the pozzolanic activity, showing in this case, lower hydration heat and developing lower compressive strength than 100% PC mortar.

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Abstract  

The chemical corrosion and the mechanical strength were studied in cement mortars containing an additive of FBCC under conditions of long-term action of sodium sulphate solution or saturated brine. The observations have shown that saturated brine is a more aggressive agent, since it leaches Ca(OH)2 and contributes to the decomposition of the C-S-H phase thus worsening the compressive strength as compared with that of mortars kept in water. The addition of 20% FBCC inhibits the leaching process and counteracts the decrease of compressive strength in mortars kept in brine. On the other hand, sodium sulphate solution changes favourably the mortar microstructure, increases of the content of small pores and improves both the compressive and the flexural strengths, as compared with those of a mortar kept in water.

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