Abstract Even if mix design (cement content, W/C ratio) has an effect on durability of concrete mixed with blended cement, curing conditions, particularly curing time, also affect concrete durability against carbonation. The choice of curing time depends on cement content, and must be adjusted to concrete design (28 day strength, W/C ratio). Concretes with a low cement content (or a high W/C ratio) must be cured longer than those having higher cement content. Finally, some correlations show that strength at the end of curing, which takes into account both mix design and curing conditions, is able to assess durability of concrete against carbonation.
Ce livre fait le point des connaissances les plus recentes sur la durabilite des betons. Il donne un vaste ensemble de resultats experimentaux. Il comporte les chapitres suivants : 1 - Introduction a la durabilite des betons (Baron,J). 2 - La durabilite et l'organisation de la qualite (Desdevises,A). 3 - Conception des betons : la structure poreuse (Buil,M et Ollivier,J-P). 4 - La maitrise de la fissuration precoce : condition de la durabilite des ouvrages (Detriche,CH). 5 - Stabilite chimique d...
The object of this work is to determine the relationship between the cracking in loaded reinforced concrete and the corrosion of embedded steel. The test specimens used in this work are three meter long beams, their constructive dispositions and the loadings are in conformity with French specifications (BAEL 83). A salt fog and a gas mixture with same percentage of carbon dioxide and atmospheric air are the two aggressive environments. The authors conclude that a damage of the 'aureole de transi...
The durability of concrete structures is greatly influenced by the curing of the concrete. Inadequate curing can result in a very weak and porous material near the surface of the concrete that is vulnerable to ingress of various harmful substances from the environment. A review is presented of the effects of methods and duration of curing on concrete properties with respect to permeability, porosity, and water absorption. Results obtained from mortar specimens that were cured using chemical memb...
This paper will discuss how during hydration of portland cement clinker and granulated slag in portland blast furnace slag cement, finely dispersed calcium silicate hydrates are formed as the major constituent of hydrated cement paste. With increasing slag content of cement, more C-S-H phases are formed, contributing to the well-known dense pore structure of pastes made of PBFS cements. Upon carbonation of the hydrated cement paste, all alkaline compounds are decomposed to form carbonates. Furth...
#1J.L. Granju(INSA: Institut national des sciences appliquées)H-Index: 4
#2J.C. Maso(INSA: Institut national des sciences appliquées)H-Index: 6
Abstract The test results reported here confirm the validity and the generality of the compressive strength law and of the model of the microstructure proposed for hardened Portland cement pastes in the first paper of this series (1). The compressive strength obeys the law R c = R o e − An or R c = R o e A e AKΓ .It depends on the capillary porosity n, linked to the product KΓ and to the hydration degree by a chain of reciprocal relations. The main features of the model so confirmed are : the gr...
#1J.L. Granju(INSA: Institut national des sciences appliquées)H-Index: 4
#2J.C. Maso(INSA: Institut national des sciences appliquées)H-Index: 6
Abstract This paper is the first of a series of three. For Portland cement pastes, it presents a model of the micro-structure and the associated compressive strength law which will be the base of the two following papers. Model and strength law involve that the most important parameter influencing the strength is the capillary porosity. They allow to foresee the characteristic properties of the pastes of the first and of the second group. At last they give informations about the structure of the...
#2Xiao-Yong Wang(Kangwon National University)H-Index: 16
Abstract In this study, a model for evaluating the CO2 uptake rate of plain concrete and limestone-powder-blended concrete in both the service and recycling phases was proposed. First, a blended cement hydration model was proposed to evaluate the content of carbonatable substances, porosity and carbon dioxide diffusivity. In the service phase, a one-dimensional carbonation model was proposed to evaluate the carbonation depth. In the recycling stage, an unreacted core model was proposed to evalua...
An accurate concrete carbonation predictive model is needed to ensure effective structural health monitoring of concrete, as a result of nonlinear behaviour of concrete carbonation and uncertainties of environmental factors affecting the progress of carbonation. In reality, the performance of a developed predictive model lies on its ability to accurately generalise (simulate) the input distribution within a given new dataset. The previous machine learning models in the studies for concrete carbo...
#1Xiao-Yong Wang(Kangwon National University)H-Index: 16
Abstract Limestone powder has increasingly been employed in the production of sustainable concrete. This research shows an optimal design framework for the design of low-CO2 blended concrete with limestone, considering strength, workability, and carbonation durability in the context of global warming. First, the purpose of the optimal design, i.e., to reduce CO2 emissions, is explained. The restrictions of the optimal design include design strength, design workability, carbonation service life i...
Last. Mark Bediako(Building and Road Research Institute)H-Index: 6
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In the presence of significant quantities of carbon dioxide (CO2) and elevated temperatures in the atmosphere due to climate change, cement-based materials are susceptible to carbonation. Blended cements are more prone to carbonation attack than Portland cement. There is a need to evaluate the carbonation resistance of blended cements in a carbonation-prone environment. This paper presents experimental findings obtained from an evaluation of carbonation resistance tests on Rice Husk Ash- (RHA-) ...
Last. José A. Amador(URI: University of Rhode Island)H-Index: 24
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Abstract Lignocellulose-amended, layered soil treatment areas (STAs) remove nitrogen (N) passively from wastewater by sequential nitrification and denitrification. As wastewater percolates through the STA, the top sand layer promotes nitrification, and the lower, lignocellulos-amended sand layer promotes heterotrophic denitrification. Layered STAs can remove large amounts of N from wastewater, which may increase their emissions of CO2, N2O, and CH4 to the atmosphere. We measured greenhouse gas (...
#1Pawan Kumar(NITJ: Dr. B. R. Ambedkar National Institute of Technology Jalandhar)H-Index: 3
#2Navdeep Singh(NITJ: Dr. B. R. Ambedkar National Institute of Technology Jalandhar)H-Index: 13
Abstract The mechanical and durability behavior of Recycled concrete aggregates (RCA) based High volume fly ash-Self compacting concrete (HVFA-SCC) has been examined through detailed experimental investigation. The article explores the overall behavior of HVFA-SCC made with 0%, 25%, 50%, 75% and 100% of RCA with alteration of Natural coarse aggregates (NCA) and in conjunction with 10% of Coal bottom ash (CBA) as alteration of Natural fine aggregates (NFA) through evaluation of several properties...
The broader use of cements with a higher content of the main non-clinker components in construction industry is one of the directions leading to the decarbonization in cement production. This contribution analyzes the properties of low-emission cements containing from 44% to 56% of Portland clinker in their composition and indicates the possibilities of wider use in the construction. The obtained results confirmed that following the appropriate technological regimes, low-emission cements can be ...
Carbonation is a deleterious concrete durability problem which may alter concrete microstructure and yield initiation of corrosion in reinforcing steel bars. Previous studies focused on the use of Artificial Neural Networks (ANN) for the prediction of concrete carbonation depth and to minimize the need for destructive and elaborated civil engineering laboratory tests. This study aims to provide improved accuracy of simulation and prediction of carbonation with an ANN architecture including eight...
