The influence of low temperature on the evolution of concrete strength

Abstract

The mechanical strength of concrete can be affected by many conditions, among them the proportion of the mixture and the influence of external agents, such as external temperatures. Thus, the objective of the paper is to analyze the influence of low temperature on the evolution of concrete strength, from the molding of tests specimens cured at various temperatures. The specimens were submitted in the first 7 days, as curing temperatures ranging from 0°C to 25°C, simulating the lowest possible value for the start of the cement hydrations reactions to the considered ideal for development resistances. The results of the experimental program demonstrated at lower cure temperatures the strength of the mixture develops more slowly, as might be expected, but also found after 14 days, the strength of the mixtures was reversed, i.e., concretes cured at higher temperatures lower values. Thus, it was concluded the concrete in cold weather can be beneficial to its mechanical performance to over time, at the expense constructive steps in normal temperature.Keywords: external agents, low temperatures cure, evolution of resistance, hydration heat of Portland cement paste.As resistências mecânicas do concreto podem ser afetadas por inúmeros condicionantes, como a proporção entre os seus constituintes e a influência de agentes externos, como a temperatura ambiente. Com isso, o objetivo deste artigo é analisar a influência das baixas temperaturas na evolução das resistências do concreto a base de cimento Portland, a partir da moldagem de corpos-de-prova curados em temperaturas variadas. Os corpos-de-prova foram submetidos, nos primeiros 7 dias, a temperaturas de cura que variaram de 0°C até 25°C, simulando as temperaturas mais baixas possíveis para o início das reações de hidratação do cimento até os valores considerados ideais para o desenvolvimento das resistências. Os resultados do programa experimental demonstraram que em temperaturas de cura inferiores a resistência à compressão da mistura se desenvolve mais lentamente, como era de se esperar, porém também verificou-se que a partir dos 14 dias, as resistências das misturas se inverteram, ou seja, os concretos curados a temperaturas superiores apresentaram valores menores. Com isso, concluiu-se que a concretagem em dias frios pode ser vantajosa para o seu desempenho mecânico ao longo do tempo, apesar de prejudicar etapas construtivas em situações normais de temperatura.Palavras-chave: agentes externos, curas a baixas temperaturas, evolução de resistência, calor de hidratação da pasta de cimento Portland.

Mechanical evaluation and hydration kinetics of cement pastes with dolomitic filler

“…According to the authors, when samples are molded and kept at low temperatures at early ages, there is no improvement in the hydration process, which may contribute to strength loss. However, Cecconello and Tutikan [39] studied the influence of low temperatures on concrete strength evolution and observed that concretes cured at lower temperatures at early ages could contribute to strength increase. The authors explain that the longer the hydration of Portland cement takes, the better the crystalline structure formation will be, thus clarifying that concretes cured at low temperatures at early ages can have a superior mechanical behavior than those cured at higher temperatures.…”

Application of the maturity method to reinforced concrete roof slabs

“…Many authors debate how temperature impacts strength gains and concrete hydration [4][5][6]. Studies show that compressive strength tends to be higher when the concrete is exposed to higher curing temperatures [7]. Fig.…”

Influence of Lowered Temperature on Efficiency of Concrete Repair with Polymer-Cement Repair Mortars

“…When the mean ambient temperature is lower than +10 °C for at least three subsequent days, special requirements apply to the execution of concrete works. The temperature of +5 °C is regarded as the boundary temperature below which the concrete mix shall be protected from heat loss [ 1 , 2 , 3 , 4 , 5 , 6 ]. The literature describes numerous cases of doing works in such temperature conditions, including the cases showing negative effects of such operations [ 7 , 8 , 9 , 10 ].…”