The influence of the curing conditions of concrete on durability after freeze-thaw accelerated testing

Abstract

This work relates the curing conditions of concrete with the damage caused by rapid freeze-thaw cycles (ASTM C 666). The "potential" durability of concrete after testing is also studied. In countries with a continental climate, the curing of concrete in summer is performed under high-temperature and low-humidity conditions, and during the winter the concrete undergoes freezing and thawing. This paper shows the experimental results of the behaviour of concrete specimens cured under climatic summer conditions and then subjected to freeze-thaw cycles. Curing of the specimens includes conditions of good and bad practice in relation to wetting and protection of the concrete. Mechanical properties, cement hydration, volume and pore sizes, oxygen permeability, chloride diffusion and water penetration under pressure tests of the concrete are assessed. These tests were performed before and after the application of the freeze-thaw cycles. Statistical analysis of the correlation among variables is also included. RESUMEN: Influencia de las condiciones de curado del hormigón en su durabilidad tras los ensayos acelerados de ciclos hielo-deshielo.Este trabajo relaciona las condiciones de curado del hormigón con los daños causados por ciclos hielo-deshielo (ASTM C 666). Estudia la durabilidad "potencial" del hormigón dañado por este ensayo. En países con clima continental, el curado del hormigón en verano se realiza con alta temperatura y baja humedad, y durante el invierno sufre condiciones de hielo-deshielo. Se presentan los resultados experimentales de probetas de hormigón curadas bajo condiciones climáticas del verano y luego sometidas a ciclos hielodeshielo. El curado de las probetas incluye condiciones de buenas y malas prácticas en relación con el curado del hormigón. Se miden las propiedades mecánicas, grado de hidratación, volumen de poros y distribución de tamaños, permeabilidad al oxígeno, penetración de agua bajo presión y coeficiente de difusión de cloruros antes y después de la aplicación de los ciclos de hielo-deshielo. Se incluye un estudio estadístico para analizar la correlación entre las variables.

The influence of curing and aging on chloride transport through ternary blended cement concrete

“…Additionally, the gel of SL cement should have a lower C/S ratio and more Al (19)(20)(21) and should be at a higher magnitude (22)(23)(24)(25), which might also cause the decrease in the penetration rate of these ions into the concretes containing this SCM. Furthermore, the slower entrance of chlorides into SL concrete is related to the composition of the BFS, which contributes to hydrated phases that are richer in Al 2 O 3 , which enhances its ability to bind chlorides (22)(23)(24)(25) compared to OPC used in this study, with low aluminate content and therefore, lower Cl binding capacity. Figure 6 shows the relationship between chloride transport and porosity through the representation of D nat,nss values obtained after the three exposure periods tested and the initial total porosity values.…”

“…The slower penetration of chlorides into concretes containing BFS in comparison to Portland cement concretes is associated with two different phenomena. The hydration of BFS favors the formation of additional C-S-H gel with a similar structure to that of ordinary Portland cement (OPC) which contributes to making the system denser, but with a lower CaO/SiO 2 ratio (18)(19)(20)(21)(22)(23)(24)(25). Al is also incorporated into the C-S-H to a greater extent (19)(20)(21).…”

Detection of the synergetic influence of chemical and microbiological factors on the properties of concrete constructions at chemical plants during the long-term service

“…However, the researchers point out that it is necessary to be careful when conducting research on concretes that have a short production time. During freeze and thaw cycles, young concretes can complete hydration, which can lead to erroneous interpretation of the data obtained [11].…”