Author(s): Daniel Wiliński, Paweł Łukowski, Gabriel Rokicki
Title: Application of fibres from recycled PET bottles for concrete reinforcement
Volume: J. Build. Chem. 1 (2016), 1-9
Keywords: PET bottles; recycling; fibres; reinforced concrete; hydrolysis
Abstract: Waste PET can be reused as partial or complete substitute of an aggregate in a concrete composition or as a concrete reinforcement. However, the main drawback of such applications is the hydrolysis of ester linkages of poly(ethylene terephthalate) in highly alkaline environment of the cement matrix. To prevent alkaline hydrolysis, the PET fibres were coated with commercially available ethylene/vinyl acetate copolymer (EVA). Effectiveness of the use of copolymer EVA as a protection layer against strong alkali solutions has been demonstrated and discussed. Chemical changes in PET fibres after alkaline treatment have been referred to mechanical properties of the fibres. Mechanical properties, like compressive and flexural strength of the composites as well as the long-term durability performance of recycled PET fibres in alkaline environment were also investigated. The preliminary results indicated that the introduction of the PET fibres does not deteriorate the mechanical strength of the concrete composite.

Author(s): Karol Brzeziński, Łukasz Kraiński
Title: Zero shear viscosity estimation using a computer simulation of Van der Poel’s nomograph
Volume: J. Build. Chem. 1 (2016), 10-17
Keywords: Zero shear viscosity; Van der Poel’s nomograph; rutting resistance; computer simulation
Abstract: The properties of asphalt mixtures depend both on the properties and the proportions of the components. Rutting resistance is related to the binder property called zero shear viscosity (ZSV). This paper presents a new method for estimating ZSV based on penetration and softening point tests by using a computer simulation of Van der Poel’s nomograph. The results have been compared with literature data. Furthermore, for the purposes of the analysis presented in this paper, a computer simulation of the nomograph was developed. The results of simulation are presented in Appendix 1.

Author(s): Piotr Prochoń, Tomasz Piotrowski
Title: Bound water content measurement in cement pastes by stoichiometric and gravimetric analyses
Volume: J. Build. Chem. 1 (2016), 18-25
Keywords: Bound water; cement paste; Bogue equitation; hydration
Abstract: The cement hydration is one of the most complex processes creating the cement matrix. The degree of hydration is a quantity of Portland clinker with gypsum, that as a whole react with water. For purposes of this analysis it was found to be directly proportional to the bound water in the cement paste specimens. Using the gravimetric method the bound water content was determined in samples by calculating the quantitative loss of the dry specimens weight after igniting to 1000°C and keeping the temperature for 5h. Obtained results were collated with theoretical stoichiometric analysis based on the Bogue and Taylor equations and XRD testing for Portland cement, CEM I 42.5. Obtained outcome has confirmed the relationship between the degree of hydration and the bound water content in cement paste. The influence of the w/c ratio and cement oxide components on bound water quantity were also noticed.

Author(s): Elżbieta Horszczaruk
Title: Influence of addition of fluidal fly ashes on the mechanical properties of underwater concretes
Volume: J. Build. Chem. 1 (2016), 26-30
Keywords: Consistence; fluidal fly ash; underwater concrete; wash-out losses
Abstract: The paper deals with possibility of utilization of the fly ash from fluidal beds as the component of underwater concrete. The concrete mixes contained various amounts of the fly ash, made and cured in different conditions, including underwater environment, were tested. The rheological characteristics of the concrete mixes has covered the flow table consistence and wash-out losses after immersion in water. The compressive strength of the concrete was also determined after various time of curing. It has been found out that, under certain conditions, the fluidal fly ashes can be valuable addition to underwater concrete mixes.

Author(s): Paweł Łukowski
Title: Influence of temperature on efficiency of superplasticizing admixtures for concrete
Volume: J. Build. Chem. 1 (2016), 31-36
Keywords: Admixture; concrete; efficiency; superplasticizer; temperature
Abstract: Temperature is one of the most important factors affecting the efficiency of polymer admixtures to concrete, yet this relation is still not fully explained. The direction of changes depends on the type (chemical nature) of the admixture, and often also on its concentration and composition of the concrete mix. Taking into consideration the big diversity of the used polymer admixtures, it is very hard to predict their temperature characteristics; this requires detailed testing. It is possible to find out, on the base of the collected data, that in the case of the new generation of the superplasticizers an increase of temperature usually leads to diminishing of the admixture efficiency. This means the necessity of increasing dosage of the superplasticizers of new generation at higher temperature.

Author(s): Dariusz Brożyna, Karol J. Kowalski
Title: Modification of asphalt binders by polyethylene-type polymers
Volume: J. Build. Chem. 1 (2016), 37-41
Keywords: Bitumen; asphalt modification; polyethylene; polymers
Abstract: This investigation tested the effects of asphalt binder modification, using polyethylene-type polymers. During the research, five different polymers were used: HDPE, LDPE, LLDPE, copolymer EBA (ethylene/butyl acrylate) and terpolymer EBM (ethylene/butyl acrylate/maleic anhydride). Those polyethylene-type polymers were used to in-lab modification of 50/70 raw unmodified road bitumen. Modified specimens were tested in terms of penetration, softening temperature and elastic recovery. Samples were aged using the Rolling Thin Film Oven Test procedure. The gathered data suggest that addition of polyethylene-type polymers to the asphalt binders reduces penetration, and increases softening temperature. In terms of elastic recovery only terpolymer EBM presented significant improvement, reaching a 75% relative elastic recovery.

Author(s): Magdalena Osial, Daniel Wiliński
Title: Organic substances as corrosion inhibitors for steel in concrete - an overview
Volume: J. Build. Chem. 1 (2016), 42-53
Keywords: Reinforced concrete; organic inhibitors; corrosion; admixtures
Abstract: Organic inhibitors have attracted considerable attention due to their promising application as admixtures in concrete protecting against corrosion of rebars. Over the last decade the use of those inhibitors significantly raised. The inhibition efficiency depends on their physical and chemical properties. This paper gives short overview of the protection of steel in concrete against the ingress of chlorides, oxygen and carbon dioxide in concrete, as species causing the corrosion of rebars. This work involves only organic inhibitors. 

Author(s): Justyna Kuziak, Piotr Woyciechowski
Title: The influence of the chloride content in cement CEM III on the chemical resistance of concrete under conditions simulating the effect of acid rain and wastewater
Volume: J. Build. Chem. 1 (2016), 54-60
Keywords: Granulated blast furnace slag cement; chloride ions; chemical resistance; acid rain; wastewater
Abstract: Chlorides content in cement is related to the production process - the sources of chlorides are mainly fuels, especially alternative fuels. Some chlorides are drawn off with by-pass powder, which is a by-product not easy for utilization. To reduce the production of environmentally noxious waste, cement producers attempt to increase the chloride content in ground granulated blast furnace slag cement (CEM III) above the value of 0.10% by weight. In European standard (EN 197-1) the limit value of chloride content in cement is generally 0.10% by mass, however, for CEM III there is a note in this standard which permits higher content of chlorides in this type of cement. The accelerated tests on the effect of the chloride content in CEM III, in the range of 0.1 - 0.5%, on the chemical resistance of concrete in solutions simulating acid rain and wastewater were performed. The solution of nitric acid and sulfuric acid was used as a solution simulating the acid rain. Solution simulating the wastewater contained ammonium sulfate, magnesium sulfate and sulfuric acid. After five weeks of exposure of concrete to corrosive solutions, weight change and the strength of the concrete samples were determined. No significant effect of the chloride content in cement over a range of tested values on the chemical resistance of concrete in environment simulating acid rain and wastewater was found.

Author(s): Alberto H. Oroza, Fabio Rojas Pimentel, Esmérida Pérez Parra, Luz M. Delgado León, Yilena García Amorós
Title: Development of two analytical methods for determination of water-soluble chlorides and sulfates in the conservation of concrete heritage buildings
Volume: J. Build. Chem. 1 (2016), 61-68
Keywords: Heritage buildings; water-soluble chlorides; sulfates; precision; accuracy; uncertainty
Abstract: The corrosiveness and pollution of the atmosphere in the Old City of Havana - Cuba, have come to be over the last decades a growing concern regarding the durability and the aesthetics of heritage and historic concrete buildings. The chlorides and sulfates present in the air are capable to deposit over the concrete and have a direct impact on the deterioration of buildings. Chloride anions induce localized corrosion on the reinforced steel, while sulfates produce severe cracking in concrete. Based on Cuban climate parameters, it is important to develop an analytical method suitable to quantify the amount of these substances in the mass of concrete. The aim of this study was to develop two analytical procedures for the quantification of water-soluble chlorides and sulfates in hardened concrete in used buildings. Basic evaluation of the precision, accuracy and uncertainty of the proposed methods was done. In order to determine the content of water-soluble chlorides, mercury(II) nitrate was used as a titrant, and mix of bromophenol/diphenylcarbazone as an indicator. The sulfates content was determined gravimetrically. The study concluded that both methods, as well as the statistical analysis performed are satisfactory, allowing the quantification of the amount of water-soluble chlorides and sulfates in concrete heritage buildings. 

Author(s): Daniel Wiliński, Jarosław Kantorowicz, Sławomir T. Wierzchoń
Title: Modelling the demand for cement: The case of Poland and Spain
Volume: J. Build. Chem. 1 (2016), 69-83
Keywords: Cement production; forecasting methods; hybrid models; SARIMAX; artificial neural network
Abstract: The paper develops a new tool for forecasting the demand for cement and tests it on the data from Poland and Spain. Predicting the demand for cement is a key issue from the perspective of the cement manufacturers. Forecasting this demand helps businesses determine, among others, the level of production, future revenue stream and purchase of raw materials. The hybrid models employed in this paper consists of Seasonal Autoregressive Integrated Moving Average with Exogenous Variables (SARIMAX) model and Artificial Neural Network (ANN). The SARIMAX model was initially used to forecast the demand for cement. The resulting forecasting errors were further corrected with ANN, which was built to account for the nonlinear tendencies that the SARIMAX technique could not identify. The forecasting errors from the hybrid model were compared with the errors from ARIMA-type and the ANN models working separately. The results indicate that the hybrid models outperform of the models used separately. If implemented, this methodology may become a powerful decisionmaking tool for cement industry. 

Author(s): Joanna Julia Sokołowska
Title: Technological properties of polymer concrete containing vinyl-ester resin waste mineral powder
Volume: J. Build. Chem. 1 (2016), 84-91
Keywords: Polymer concrete; vinyl-ester resin; recycling; waste mineral powders; consistence testing
Abstract: The aim of the presented research was to assess the possibility of using waste mineral powder (remaining after preparation of aggregates for mineral-asphalt composites) as a component of polymer concrete with vinyl-ester resin used as the binder. The evaluation was done in terms of chosen technological properties, namely: consistence and temperature changes during setting of polymer mix. The first part of the paper contains material characteristics (chemical composition, particles size distribution, specific surface area) of mineral powders - both commonly used quartz powder and waste mineral powder - applied into polymer concrete as the finest fraction of aggregate. The second part of the research was focused on characteristics of setting of micro-mortars with vinyl-ester resin modified with the waste powder and consistence of concrete mixes prepared with use of those micro-mortars. Taking into consideration obtained data, author determined the optimal compositions of concrete with vinyl-ester resin and waste mineral powder of technical properties not worse than in case of regular (non-modified) one, but at the same time definitely more ecological.
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