Will Blended-Cement Systems with Similar Chloride Penetration Potentials Resist Similarly to Corrosion?

The capacity of concrete to prevent chloride ions penetration represents a key durability factor for steelreinforced structures exposed to de-icing salts and/or marine environments. Although blended-cement systems are commonly characterized with accelerated chloride penetration tests developed for Portlandcement concrete (e.g. the ASTM C1202 method), their microstructures and pore solutions are very different. This study aims to illustrate how the full potential of blended-cement systems to resist chloride ingress (and thus, chloride-induced corrosion) may not be justly disclosed by these accelerated tests using electrical current, even when tested after three months of curing. A Portland-cement-only mortar and five binary blended-cement mortars containing typical dosages of fly ash, slag, metakaolin, glass powder or rice husk ash were characterized using the ASTM C1202 chloride penetration test, bulk resistivity measurements and pore solution resistivity measurements. The results showed similar very low chloride penetration potential after three months for the investigated systems (except for the slag system which showed a low potential). The microstructure was densified with time particularly for systems with fly ash or glass powder, as shown by comparing bulk resistivity measurements after three months and one year of curing. However, measurements of the pore solution resistivity suggested a reinterpretation of the observed trends and the glass powder showed unique features for long-term resistance to chloride-induced corrosion. Finally, this work illustrates the importance of understanding the effects of supplementary cementitious materials on both the microstructure and the pore solution, while motivating further work on complementary aspects such as chloride migration coefficients, chloride binding, porosity distribution, or interfacial transition zone

Conséquences sur les changements climatiques d'initiatives de développement durable: regard sur le secteur du ciment Portland

À la suite de la ratification de l’Accord de Paris sur le climat en 2016, le Canada s’est fixé un objectif de réduction de ses émissions de gaz à effet de serre (GES) de 30% en dessous du niveau de 2005 d’ici 2030. L’atteinte de ces objectifs requiert l’adoption d’initiatives de développement durable ambitieuses et progressives dans tous les secteurs industriels. Un des secteurs fortement interpellés est celui de la production de ciment Portland, principal élément liant du béton. Les procédés de fabrication du ciment Portland génèrent environ 7% des émissions mondiales de GES produits par les activités humaines et près de 80% de ceux provenant de l’industrie de la construction (Aïtcin et Mindess, 2017). Bien qu’il ne représente que de 10 à 12% de volume total d’un béton ordinaire, le ciment représente de 74% à 81% des émissions totales de GES (Boesch et Hellweg, 2010). Ces émissions découlent en grande partie de la production du clinker, composant majeur du ciment Portland

Mécanismes d'action des fines et des granulats de verre sur la réaction alcali-silice et la réaction pouzzolanique

TOULOUSE-INSA (315552106) / SudocSudocFranceF

Introducing economic actors and their possibilities for action in LCA using sensitivity analysis: Application to hemp-based insulation products for building applications

International audienc

Role of the nature of reaction products in the differing behaviours of fine glass powders and coarse glass aggregates used in concrete

WOS:000313369400019International audienceThis paper deals with the incorporation of glass cullet in cement-based materials. The aim is to help understand the differing behaviours observed depending on the particle size of the glass: the use of fine powders usually improves the concrete properties due to pozzolanic reaction, while coarse aggregates are generally detrimental for concrete due to alkali-silica reaction. It is shown that the lack of swelling of gels resulting from the reaction of glass fines can be partly due to the nature of these gels. The comparative investigation carried out on reaction products resulting from glass grains of various sizes, in the presence of both portlandite Ca(OH)(2) and C3S (tricalcium silicate: 3CaO center dot SiO2), has shown that glass aggregates produce detrimental gels while glass fines produce gels that help to improve concrete properties

Use of fine glass as ASR inhibitor in glass aggregate mortars

International audienc