In the production of cement and concrete, mechanical and durable properties are essential, along with reasonable cost and sustainability. This study aimed to apply an evaluation procedure of the level of sustainability of mixtures of high-performance concretes (HPC) with various eco-friendly supplementary cementitious materials (SCM). The major supplementary cementitious materials (SCMs), namely, volcanic pumice pozzolan (VPP), Class C and F fly ash, ground granulated blast furnace slag of grade 120, silica fume, and metakaolin, were included. Twenty-seven concrete mixtures were analyzed using a previously presented comprehensive material sustainability indicator in a cost-effective variant. The results indicated that the rank of the concretes differed at 28, 56, and 91 days after concreting. In addition, the study showed no correlation of strength and diffusion parameters with sustainability indicators. Finally, this study will contribute to the optimal selection of mixtures of HPC with VPP in terms of sustainability, cost, and durability for future implementation in reinforced concrete bridge deck slabs and pavements. The values of sustainability indicators for pumice-based mixtures were compared with those for other SCMs, highlighting the sustainable performance of volcanic ash-based SCM.
Since concrete is one of the most important and useful materials in the construction sector, which, unfortunately, has an adverse impact on the environment, it is evident that correct procedures for designing and/or assessing concrete structures need to be created. Model Code 2020 with the focus to sustainability stated to be one of main aspiration goals, which will have implications for subsidiary performance requirements critical to structural design, integrate life cycle perspective, reliability and performance based concepts and end-of-service-life issues. Evidently the combined impact of the service life and relevant safety level of structures on the economical and environmental aspects desire full consideration of engineers and stakeholders. Consideration is also given to energy and raw material costs, as well as to environmental impact throughout the life cycle – e.g. due to emissions.
Probabilistic procedures considering the durability with respect to corrosion of reinforcement caused by aggressive substances are widely applied; however, they are based on narrow assumptions. The aspects need to be evaluated both in terms of the search for suitable application of the various experimental results and in terms of their impact on the result of the stochastic assessment itself. In this article, sensitivity analysis was used as an ideal tool to prove how input parameters affect the results of the evaluation, with consideration of different types of concrete (ordinary or self-compacting with and without fibres). These concretes may be used in aggressive environments, as an industrial floor or as a part of the load-bearing bridge structure. An example of a reinforced concrete bridge deck was selected as the solved structure. The results show that in the case of a classic evaluation, a larger amount of fibre reports a lower resistance of concrete, which contradicts the assumptions. The sensitivity analysis then shows that self-compacting concrete is more sensitive to the values of the diffusion coefficient, and with the consideration of fibres, the effect is even greater.
Reinforced concrete structures are typically exposed to a combination of aggressive substances and mechanical stresses, which contribute to fast degradation. The present research was conducted to evaluate five time-dependent parameters from several different tests, namely compressive strength, static modulus, dynamic modulus, surface, and bulk electrical resistance. Some parameters were obtained using destructive testing (DT) and some using non-destructive testing (NDT). Due to the correlation and calculation of regression curves, it was possible to compare the correlation of parameters important for estimating the durability of reinforced concrete structures in relation to degradation and corrosion. Concrete of C40/50 grade was examined in several time periods, and the parameter relationships were analysed. At the same time, a statistical evaluation was carried out, and therefore the study contains the average values and standard deviations of all measured parameters. The results show that the compressive strength and the electrical resistivity of the surface and bulk have a high correlation. In contrast, the dynamic modulus and electrical resistivity have low linear correlation, but it was possible to apply a quadratic curve with a high degree of fit. For the comparison of static elastic modulus and electrical resistance, the quality of the quadratic regression model was low but sufficient. The results show that, for structural concrete, the presented NDT methods can be used to estimate other parameters obtained from the DT methods.
Efficient sustainability management of concrete structures requires the use of tools which allow material, technological and construction variants to be quantified. The present contribution, apart from discussing the issue of sustainability of concrete structures, focuses on the quantification of concrete resistance to degradation. An indicator expressing quality, with regard to sustainability, is determined using information on concrete performance characteristics, service life and eco-costs, enabling the quantification and comparison of various cases. Cradle-to-gate system boundary and the full probability method are used. The aim is to propose a suitable methodology which can simplify decision-making about the design and choice of concrete mixes from a wider sustainability perspective, as an extensional and integrating approach to evaluating load-bearing capacity and durability. Two case studies of probabilistic sustainability quantification are shown using sustainability potential indicators for two different definitions of service life (due to carbonation of concrete and freeze/thaw effects), considering also the concrete performance’s and impact on the environment.
The sustainability of the construction industry requires new perspectives on existing techniques. For example, fibre concrete has been an integral part of the construction industry for many years and its contribution to enhancing the properties and use of concrete is undeniable, but there are still some questions that need to be answered. The present paper showed the possibilities of statistical evaluation of crack mouth displacement (CMOD) tests performed on 24 fibre concrete specimens. The aim was to point out possible pitfalls and to propose measures based on statistics. The geometrical properties of all samples were determined and correlated with the results of the CMOD test. In this paper, a procedure was considered to compare two different concretes with different fibres at CMOD level. Correlations between geometry and CMOD test results were also demonstrated.
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