Thermal Treatment of Self-Compacting Concrete in Cast-<i>In Situ</i> Construction

Abstract

Self-compacting concrete (SCC) is an innovative concrete that does not require vibration for placing and compaction. Thermal treatment (TT) of SCC can significantly accelerate the strength growth during cast-in-situ construction. This paper presents a technology of TT of structures for cast-in-situ construction with SCC. Application of this technology allows to reduce the turnover of formwork, the labor costs for construction, and the construction period. We also studied the issue of strength development of SCC during TT. For our study, we used SCC of grade C25. Test samples were cured with TT by infrared radiators for 7, 9, 11, 13, 16 and 24 hours. Then warmed samples were tested for compressive strength after 0.5, 4, 12 and 24 hours of cooling period. Study was carried out on the basis of analyzing, generalizing and evaluations of experimental data. A mathematical model is proposed for determining the compressive strength of SCC after one day of curing of SCC with TT.

Heat Treatment of Self-Compacting High-Strength Concrete in Cast <i>In Situ</i> Construction Using Infrared Rays

“…High-strength concrete (HSC) is a durable material, and it has superior physical and mechanical properties [1][2][3]. Self-compacting concrete (SCC) improves productivity and working conditions due to the elimination of vibration and compaction, and helps in achieving higher surface quality, and it is also suitable for placing in structures with congested reinforcement without vibration [4][5][6]. The shortest time of construction, the execution of works in different climatic conditions etc.…”

“…above 500 °C, however, HT at 350 °C followed by short mechanical treatment has led to a good result. It is worth noting that the optimum temperature for HT of concrete is 80-95°С [6][7][8][9], otherwise moisture may evaporate from the concrete. During HT of concrete, it is important to take care against the evaporation of moisture from the concrete mix.…”

“…The technology of heat treatment of the laid and compacted concrete mix with the use of infrared heating with gas burner and a two-chamber transparent cover for infrared rays [6] provide conditions for the normal course of the chemical reaction of hydration, curing and strength development of concrete. However, the disadvantage of infrared heating using gas burners is the necessity to create a closed space in the form of a shelter or tent to protect gas burners from blowing by the wind, which increases the laboriousness of its implementation.…”