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• Lightweight concrete containing scrap-tyre-rubber-based aggregate. • A wide set of structural, mechanical, thermal and hygric properties. • Improved thermal performance, approved thermal stability up to 300 °C. • Unaffected water transport parameters, while water vapour transition increased. • Non-bearing lightweight material having benefits to the environment and economy. Increasing amount of waste tyres represents a global problem as tyres can pose a risk to the environment if not treated properly. Recycling of waste tyre rubbers in civil engineering as aggregate in cement concrete can be an effective environmental and economic approach. As problems associated with the use of waste tyre rubber in concrete production are not completely understood, a detailed analysis of rubber concrete prepared from used tyre rubber-based aggregate involving testing of its mechanical, basic physical, microstructural, hygric and thermal properties, and behaviour after exposure to elevated temperatures is presented in this paper. Testing of mechanical performance included measurement of compressive strength, flexural strength, secant and dynamic modulus of elasticity. Thermal conductivity was determined in the dependence on moisture content, from the dry to fully water saturated state. Dry volumetric heat capacity was also tested. Specific attention was paid to the hygric performance of rubberized concrete that was characterised by the water and water vapour transport parameters. Investigation of concrete properties after its thermal exposure included testing of mass loss, mechanical resistance, bulk density, and thermal conductivity that was tested as property having direct relation to concrete structural parameters. The use of scrap-tyre-rubber aggregate resulted in a decrease of the unit weight, worsening in mechanical parameters and a significant reduction in thermal conductivity of prepared rubberized concrete. Rubber-based aggregate almost did not affect water transport properties, while water vapour transport properties increased with rubber amount in the mix. No significant changes on concrete characteristics related to rubber incorporation occurred at temperatures up to 300 °C. However, after exposure to 400 °C, significant changes in measured concrete properties were observed, which was in line with the thermogravimetric analysis of the used tyre-based rubber. Nevertheless, based on rubberized concrete functional properties at common ambient conditions it can be considered as an alternative lightweight material, bringing benefits to the environment and economy as it is produced from crap available in a large amount and at a negligible cost. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lightweight mortars for repair of historical masonry were designed and tested. • Silica sand was partially/fully replaced by crushed pumice of a similar grain size. • The lightweight mortars met the technical requirements for remediation mortars. • The heritage conservation requirements for compatibility were also met. • Mechanical resistant, durable, vapor permeable and thermal insulation mortars. The subject of the presented research was an experimental analysis of physical, engineering and durability parameters of lightweight mortars intended for the repair of historical buildings. Compatibility criteria, the requirements of technical standards and guidelines, and last but not least, previously published research results dealing with the development of mortars for repair delicate historic structures were taken into account in the design of mortar composition. Crushed pumice of a similar grain size was used to lighten the reference lime-based mortar and natural hydraulic lime mortar with quartz filler. Replacement of quartz sand with pumice was 25, 50, 75 and 100% by volume. The use of pumice allowed the fundamental physical, mechanical, hygric, thermal and durability parameters of the lightweight mortars to be such that they met the standard requirements for repair mortars and the heritage conservation requirements for compatibility with the original materials of historic masonry. The main finding was the fact that by replacing sand with pumice, a significant increase in the porosity of the mortars was achieved, while maintaining sufficient mechanical strength due to the pozzolanic reaction of the pumice. Mortars based on natural hydraulic lime have become more resistant to frost and salt crystallization. The advantage of the developed mortars was their low thermal conductivity and high water vapor permeability, which made them suitable for use on damp masonry, which is a substantial scientific contribution of the manuscript. [ABSTRACT FROM AUTHOR]

• Thermally activated extracted shale (ES) from fertilizer carrier. • The pozzolanic activity of activated ES was documented. • High compactness and mechanical strength of PC blends. • Reduced heat of hydration of PC/activated ES mixtures. • OPC can be safely replaced up to 20 % by mass of waste that has no other use. This research concerns the analysis and application of extracted shale from mining waste at the Lubelski Węgiel „Bogdanka" S.A. coal mine in Poland. Various analyses were performed on both raw and thermally activated forms of extracted shale, and then the thermally activated one was used as a partial cement substitute in a PC-based paste. In order to reduce the required additional energy, the activation temperature for the extracted shale was chosen to be 600 °C according to the simultaneous thermal analysis measurement. Chemical, mineralogical, physical, and morphological analyses, thermogravimetry, and pozzolanic activity tests of raw and thermally activated extracted shale were conducted. The Portland cement pastes containing either 10 wt%, 15 wt%, or 20 wt% of thermally activated extracted shale were compared to a reference plain cement paste. Cement pastes with the thermally activated extracted shale were studied in the fresh and also hardened state after 7, 28, and 90 days of setting. Furthermore, mechanical, structural, and microstructural properties were measured and compared with the reference. Simultaneous thermal analysis with a mass spectrometer (STA-MS), isothermal calorimetry, X-ray powder diffraction (XRD), and strength activity index (SAI) evaluation were used to assess the evolution and rate of the pozzolanic reaction. All the performed analyses confirmed the pozzolanic activity of the thermally treated extracted shale and its potential in cement industry applications. The extracted shale also acted partially as a microfiller. The use of calcined extracted shale reduced the porosity of the cement matrix and increased its flexural and compressive strength. For 90-day samples, a slight hindrance in the precipitation of final substances was observed as a result of different kinetics of hydration and pozzolanic reactions. Taking all of the results into consideration, the coal mining waste – calcined extracted shale – can find use as a partial cementitious substitute for up to 20 wt%. [ABSTRACT FROM AUTHOR]

Although landfilling and disposal into the ocean present still the most common methods used in the sewage sludge management, the share of recycling and reuse based on drying and incineration procedures continuously increases during the last decades. In this paper, an energy-efficient thermal treatment of sewage sludge is proposed, aimed at its use in blended cements. A practical application of the designed treatment is performed for the sewage sludge obtained from the municipal wastewater treatment plant in Patras, Greece. The material characterization shows that the sludge thermally treated at 700 °C has significant amounts of silica, alumina, calcium oxide and iron oxide, while the content of amorphous phase is 41%, which results in a good pozzolanic activity. The mechanical properties of hardened cement pastes prepared using blended Portland cement-thermally treated sewage sludge binders are after the 28-days curing period not satisfactory yet, indicating that a substantial part of the sludge acts still as filler only. This discrepancy between the pozzolanic activity and mechanical tests can be explained by too coarse sludge particles which slow down the pozzolanic reaction. The results of chemical tests show that the safe limit for the practical use of sewage sludge as partial Portland cement replacement is 10%, which is mainly due to the relatively high content of chlorides and alkalis. This limit can though be increased by the removal of soluble salts from the raw sludge using water treatment. The life cycle assessment analysis of the blended cements shows that the decrease in energy consumption is nearly 10% for each 10% of sewage sludge in the blend. The emission of greenhouse gases during the thermal treatment of the sludge is found almost twenty times lower than in the Portland cement production. The cost analysis reveals substantial economical benefits related to the application of sewage sludge as partial cement replacement. [ABSTRACT FROM AUTHOR]

Abstract: Three systems of brown coat-renovation plasters for restoration of building structures damaged by moisture and salt efflorescence are analyzed, and their properties are compared with reference lime plaster. In the experimental part, measurement of bulk density, matrix density, open porosity, pore distribution curves, chloride binding isotherms, moisture and chloride concentration profiles is performed. The obtained data are used in the calculations of moisture dependent moisture diffusivity and concentration dependent chloride diffusion coefficient. The experimental and computational results show that all three systems can have beneficial influence on the restored building structures but they should be used with caution, taking into account the properties of the material of load bearing wall and the conditions for water and salt transport in the wall including their possible sources after reconstruction. The measured water and salt transport and storage parameters may contribute to the improvements in service life assessment if they are used as input parameters in computational modeling of water and salt transport and accumulation in the load bearing wall-renovation plaster system. [Copyright &y& Elsevier]

Abstract: Basic water and salt transport and storage properties of Mšené sandstone, a material frequently used in historical buildings on the Czech territory for many centuries, are studied in the paper. Moisture diffusivity and water vapor diffusion resistance factor represent the water transport parameters, sorption isotherm and water retention curve water storage parameters, ion binding isotherm the salt storage parameter and salt dispersion coefficient the salt transport parameter. Experimental results show that the analyzed material has mostly favorable water and salt transport and storage properties which can be attributed mainly to its open pore structure and to its negligible amount of small pores. As a consequence, a risk of damage due to salt crystallization and due to ice formation seems to be low for this material. This makes it appropriate for application in severe conditions, such as the permanent exposure to water or salt solutions. [Copyright &y& Elsevier]

Coupled water and chloride transport in cement mortar is analyzed experimentally in the paper. Samples with initial moisture content corresponding to 45% relative humidity are subjected to one-sided sodium chloride-in-water solution uptake, and moisture profiles and chloride concentration profiles are determined in three chosen time intervals. In the evaluation of measured moisture profiles and chloride concentration profiles, diffusion model is employed. Moisture diffusivity is determined as function of moisture content and chloride diffusion coefficient as function of chloride concentration using two methods commonly used for analysis of moisture profiles, namely the double integration method and the Matano method. The highest values of both coefficients are obtained by Matano method for the curves corresponding to 24 h exposure to the solution, the lowest values by Matano method for 168 h, the results obtained by double integration method are in between. The complementary experiments with distilled water as penetrating liquid performed for the sake of comparison do not show this feature. It is observed that water transport in the initial time period is for the chloride solution faster and in later times slower than for distilled water. Therefore, the observed differences in the calculated apparent values of moisture diffusivity and chloride concentration coefficients are attributed to the fact that Cl- and Na+ ions are adsorbed on the pore walls faster than water molecules. This effect should be included into the mathematical models using ion binding isotherms. [Copyright &y& Elsevier]

Hygric properties of porous building materials are important for hygrothermal analysis. Their experimental determination is however not always reliable, shown by the discrepant results from different laboratories on the same materials. In this study, a recent round robin campaign initiated by KU Leuven (Belgium) and participated in by eight institutes from different countries is reported. Ceramic brick was selected as the target material. The bulk density and open porosity from vacuum saturation tests, the capillary absorption coefficient and capillary moisture content from capillary absorption tests, and the vapor permeability from cup tests were measured. Results were analyzed statistically and compared with a previous round robin project, EC HAMSTAD. The reproducibility errors for determining the capillary absorption coefficient were noticeably reduced when compared with the EC HAMSTAD project, and the different laboratories in the present study obtained similar results from vacuum saturation tests and capillary absorption tests without a common protocol. For cup tests, large inter-laboratory discrepancies still exist. However, with a stringent common protocol different laboratories achieved consistent results. For all properties a common protocol did not change the average results of all laboratories. • Errors for measuring capillary absorption coefficient are much smaller than before. • Vacuum saturation test and capillary absorption test do not need a common protocol. • Large discrepancies still exist for cup test results from different labs. • A stringent common protocol reduces the scatters for cup test in different labs. • A common protocol does not change the mean value of all labs for studied properties. [ABSTRACT FROM AUTHOR]

Abstract Energy demands of current buildings present an important problem for building designers and engineers. However, the necessity to retrofit building envelopes and achieve a better thermal performance is substantially limited by the economic viability. Despite of the environmental benefits accompanied with enhanced thermal stability, a complex evaluation of the impact of reconstruction works from various perspectives is still needed. In this paper, a quantification of physical, social, economic, and environmental benefits resulting from the application of exterior thermal insulation system to an institutional building is presented. The temperature profiles in the wall cross-section are used for the assessment of the effect of expanded polystyrene boards. The annual energy consumption and carbon emission production is found to decrease by 46% as the result of better thermal performance. The improved social comfort is confirmed by the evaluation of predicted mean vote characterizing the average heat sensation of building occupants. The carbon payback of 3.24 years refers to low initial environmental burden in proportion to obtained energy savings. However, full investments recovery rate varying from 43 to 60 years in dependence on applied economic scenarios reaches almost the lifetime of used materials, which presents a substantial barrier despite of the discounted cost savings of 180,000 Euros during the 60-year lifespan. [ABSTRACT FROM AUTHOR]

Technogenic pozzolans present a diverse group of materials. They differ in their origin, chemical and mineralogical composition, granulometry, or amorphous content. However, the analysis of their properties before utilization as supplementary cementitious materials is often insufficient which may lead to unexpected results in some cases. In this paper, a system of physical and chemical techniques for the characterization of technogenic pozzolans is proposed, which takes into account both functional and environmental aspects. The system is hierarchical and consists of three sets of methods which assess consecutively the fundamental physical and chemical prerequisites, reactivity, and performance in a blend with Portland cement. The practical application of the methodology is demonstrated for the example of fly ash from a coal power plant as the most common technogenic pozzolan. Experimental results show that the proposed system has good prerequisites to serve as a good guidance for both research and building practice. [ABSTRACT FROM AUTHOR]

• Illitic calcined shale have great potential as low-energy and low-carbon SCM. • The packing density of blended cement paste decreases, but it increases for mortar. • The flowability depends on the particle size distribution and the specific surface area. • Blended cements with illitic calcined shale show the CH-reduction and the pore size refinement. • The compressive strength of blended cements is higher than the OPC mortar 90 days. The effects of two illitic calcined shales as supplementary cementitious materials (SCMs) on the performance of ordinary Portland cement (OPC)-based pastes and mortars were investigated. The packing density of blended cement pastes and mortars were predicted with compressible packing model (CPM). The water film thickness (WFT) and flowability were calculated and measured. Early hydration was described by calorimetric curves and the hydration microstructure was identified by X-ray diffraction (XRD), differential thermal analysis (DSC/TG), and pore size distribution (MIP). The compressive strength was tested at 2, 7, 28, and 90 days. The results showed that the partial replacement of OPC by illitic calcined shale decreased the packing density and the flowability of cement pastes but this does not occur for standard mortars. For blended cements, the hydration products were similar to that corresponding to OPC, the pozzolanic reaction contributed from 28 days to the densifying of solid structure and it was also noticed the pore size refinement that improved the compressive strength at later age. [ABSTRACT FROM AUTHOR]

• Suitability of wood fiber boards for interior thermal insulation systems is analyzed. • Two-layer soft-hard fiberboards system can cause extensive hygric straining. • Hygric performance of capillary active fiberboard with water vapor retarder is satisfactory. • Energy performance of both systems is very good. Two interior thermal insulation systems based on wood fiberboards are analyzed. The first system is composed of soft and hard fiberboards, the second one utilizes a capillary active fiberboard with incorporated water vapor retarder. The hygrothermal and energy performance of the systems in the climatic conditions of Central Europe is assessed using a combination of experimental and computational methods. A laboratory critical experiment is performed at first. The measured temperature and moisture profiles are then used for the validation of computational model of coupled heat and moisture transport, which is applied for hygrothermal and energy simulations. After the successful validation procedure, the model is used for the annual assessments. The energy assessment of the two-layer system shows excellent results from the point of view of energy savings (79 % improvement) but its hygrothermal assessment reveals possible shortages related to excessive hygric straining of the wall on the exterior side. The capillary active insulation system with water vapor retarder, which is able to keep moisture in the envelope within the hygroscopic range, exhibits only slightly worse energy performance (66 % improvement) but much better hygric performance than the two-layer system. [ABSTRACT FROM AUTHOR]

• Calculation of moisture induced strains is presented. • Effective coefficients of hygroexpansion are calculated via homogenization. • Principles of both analytical and numerical homogenization are outlined. • Moisture changes are acquired through coupled heat and moisture transport. • All numerical simulation are supplemented by experiments. A micromechanics based approach is outlined in this paper to predict evolution of moisture induced strains in spruce wood. Both analytical and numerical homogenization techniques are adopted first to provide estimates of effective coefficients of hygroexpansion to be multiplied by the current change in moisture content. This latter quantity is addressed next within the framework of non-Fickian constitutive model. Experimental measurements of coefficients of hygroexpansion exploiting the digital image correlation as well as determination of moisture transport using the cup model are carried out to support both applicability and numerical implementation of the presented approach. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Wood chips ash as eco-friendly mineral admixture in mortar mix design. • Re-entry of the waste (biomass ash) in the material cycle. • Eco-efficient mortars with good functional properties. • High strength activity index and pozzolan effectiveness coefficient. • Energy savings and reduction of pollution in mortars production. Abstract Wood chips ash coming from biomass heating plant is studied as an eco-friendly mineral admixture in mortar mix design. The raw material was mechanically activated by milling in a vibratory disc mill to a degree of fineness comparable to cement. For the mortars with ash dosage, basic physical, mechanical, hygric, and thermal properties is accessed. The mortars with partial Portland cement replacement with wood chips ash exhibited good functional properties for all studied ash dosages. With increasing amount of the ash used, the average pore diameter decreased due to the partial filler effect of WCHA in mortar mix. The strength activity index was very high for all studied mortars and gave evidence of the wood chips ash pozzolanity. The pozzolan effectiveness coefficient varied from 1.52 to 0.59, which proved the pozzolanity of the studied ash and synergic effects in the Portland cement-ash-water system. The results of leaching tests showed, the chlorides contained in ash were safely immobilized in the silicate matrix. The environmental evaluation revealed decrease in both carbon dioxide production and energy consumption by the use of wood chips ash in mortar mix. For the mortar with 20% substitution of Portland cement with wood chips ash, it represents 15% of CO 2 and 16% of energy, as compared with the reference mortar mix. As the developed mortars possess good functional and environmental parameters the analyzed wood chips ash can be considered as an eco-efficient low-cost alternative to other pozzolans for production of blended binders. [ABSTRACT FROM AUTHOR]

Three different types of plastic waste replacing up to 50% of natural aggregates are used in concrete mix design. A wide set of basic physical, mechanical, thermal, and hygric properties of developed concretes is determined and their assessment is made using a comparison with reference data. The mechanical parameters, though decreasing with the increasing amount of plastic aggregates, are found satisfactory for non-bearing concrete structures. The up to seven times lower thermal conductivity, as compared with the reference material, provides an evidence of greatly improved thermal insulating capabilities. The hygric properties of designed concretes are characterized by an increase of water and water vapor transport parameters and a decrease of water vapor adsorption capacity with the increasing amount of plastic aggregates. Based on the obtained experimental results, a conclusion can be made that the designed lightweight concretes containing plastic waste aggregates present a prospective solution from the points of view of both plastic waste disposal and improvement of buildings' energy efficiency. [ABSTRACT FROM AUTHOR]

• Fly ash (FA) and boiler slag (BS) were used to improve external and base coat renders properties. • The renders with BS has high resistance to salt crystallization. • Usage of FA enhances renders resistance against freezing and thawing. • Ethylene vinyl acetate copolymer (EVAC) improves the adhesion of renders with FA and BS. The effect of the use of boiler slag (BS) and fly ash (FA) admixtures in cement-lime renders for an application in repair of salty masonry was investigated. For masonry walls with high degree of salinity, renders with incorporated BS were designed. For structures of a low degree of salinity, external renders were prepared without BS. The mix of perlite and silica sand was used as fine aggregate. In all prepared materials, methyl cellulose was added. In chosen mortars, ethylene vinyl acetate copolymer was inmixed to improve functional and performance characteristic of final products. For the developed renders, comprehensive tests of fresh and hardened mortars properties were conducted, including the measurement of adhesion, water contact angle, mercury pore size distribution, thermal properties, frost and chemical resistance. The microstructure and morphology of the developed mortars was observed using scanning electron microscope SEM. The hardened products were analyzed also by Fourier transform infrared (FT-IR) spectroscopy. The designed renovation renders have satisfied the criteria of WTA 4–9-02 directive. The renders yielded compressive strength from 5.1 to 6.9 MPa. Frost resistance was greatly improved by the 20% replacement of Portland cement with FA. Base coat renders exhibited good resistance to Na 2 SO 4 crystallization. The use of ethylene vinyl acetate copolymer enhanced the adhesion of renders to substrate. [ABSTRACT FROM AUTHOR]

• Non-hydrophobized perlite lightened renders based on different binders. • A wide set of structural, mechanical, thermal, hygric, and durability properties. • The use of perlite positively affects functional properties and durability of renders. • Lime- and natural hydraulic lime-based thermal insulation and repair mortars. • Cement-lime renders are unadvisable for repair of historical buildings. To meet today's increasing requirements on the quality of life and thus indoor air climate, new advanced construction materials are under research and development. Specific issue represents repair and renewal of old or historically valuable buildings, where the newly applied materials must be compatible with those originally used in the past. Taking into consideration the necessity to decrease the energy consumption of existing buildings with valuable aesthetic facades and appearance, use of repair renders with improved thermal insulation performance represents acceptable solution to adopt the present building stock to actual thermal requirements. In this paper, complex characterization of non-hydrophobized lightweight renders designed at once for repair and thermal insulation purposes was performed. In composition of designed materials, silica sand was partially or fully replaced with expanded perlite of the similar grain size distribution, whereas the workability of fresh renders was maintained on the same level. Among broad experimental campaign, structural parameters, moisture and heat transport and storage properties, and mechanical parameters of the hardened renders were assessed in dependence on time of samples maturing. Frost resistance test was conducted to characterize renders durability. The use of lime and natural hydraulic lime in composition of perlite lightened mortars enabled to meet all the criteria on rendering and masonry mortars taking into consideration their functionality, compatibility, durability and thermal insulation performance. These mortars well found usable for repair of historical masonry and even in conservation of heritage protected buildings. On the other hand, the cement-lime renders were found to be incompatible, too rigid and less permeable both for water and water vapor than required by culture heritage authorities, related technical standards and directives for repair renders. Nevertheless, these can find use in the construction of new buildings as thermal insulation and general purpose mortars. [ABSTRACT FROM AUTHOR]