The Preliminary Concrete Delay Duration Influence on its Properties at Thermal Processing by Hot Air

Abstract

Reducing energy consumption in the manufacture of concrete products of factory production is always an urgent task. The use of heated air for creating soft modes of heat treatment of concrete products is proposed. The influence of soft heat treatment modes on the dynamics of the concrete samples strength at an early age has been established. The expediency of using soft heat treatment modes with the obligatory use of hardening accelerators is shown. With this approach, the heat treatment of concrete samples with heated air contributes to increasing the concrete compression strength in the early term of hardening: at the age of 1 day 1.94 ... 2.12 times; at the age of 3 days 1,25 ... 1,41 times.

Effect of step heat treatment modes on the physical-mechanical properties of concrete

“…The publications [6][7][8][9] show developments regarding the combined method of solar heat treatment of concrete and reinforced concrete products (in closed forms) using air heated in a solar energy collector or in an electric air heater. The indicated method can be applied for the feasibility study in areas with different climates.…”

“…The indicated method can be applied for the feasibility study in areas with different climates. The papers [7,8] give experimentally grounded recommendations regarding the impossibility of introducing concrete pre-curing during the studied soft regimes of heat treatment. The article [9] shows the features of heat treatment of concrete pavement slabs with air, heated in a solar energy collector, in the conditions of the city of Poltava (Ukraine).…”

“…The article [9] shows the features of heat treatment of concrete pavement slabs with air, heated in a solar energy collector, in the conditions of the city of Poltava (Ukraine). It is experimentally found that heat treatment under soft conditions improves the structure of cement stone, promotes the formation of fine-dispersed, stronger tumors [6][7][8][9][10]. Investigation of this combined method of solar heat treatment was carried out with the continuous flow of heated air to the chamber during the chosen period (with subsequent concrete thermosetting).…”

“…The common advantage of a number of methods of solar heat treatment of concrete and reinforced concrete products in relation to the traditional methods of their heat or heat-moisture treatment is not only energy saving, but also soft regimes, which accelerate their hardening [1][2][3][4][6][7][8][9].…”

“…The general problem related to any of the methods of solar heat treatment of concrete and reinforced concrete products is a different intensity of the arrival of solar energy to the heat transfer surface both during the year and during the day. The use of an additional (reserve) heat source can solve this problem [1][2][3][4][5][6][7][8][9].…”