A pull-out method for evaluating the early freezing performance of concrete

Abstract

A pull-out method for evaluating the early freezing performance of concrete. In winter construction, the mechanical properties of concrete are reduced due to the influence of low temperature, especially the negative temperature is affected by freezing ice. Because the freezing brings additional strength to concrete, it is difficult to accurately grasp the mechanical properties of concrete under negative temperature environment in winter construction, resulting in winter construction. The construction progress is affected, the construction quality control is difficult to guarantee, and the strength development of the concrete on site cannot be timely and accurately fed back, which greatly increases the probability of hidden dangers in the project quality. The present invention selects the adjacent concrete area I and concrete area II in concrete engineering, obtains the temperature rise time Δt from the concrete area I to the ice-free state, heats the concrete area I according to the temperature rise time Δt, and heats the heated concrete Pull-out tests were performed on the area I and the unheated concrete area II, and the early freezing performance of concrete was evaluated by comparing the pull-out force values. The invention is used for evaluating the freezing performance of concrete.

Description

technical field [0001] The invention belongs to the field of concrete detection, and in particular relates to a method for evaluating the early freezing performance of concrete by drawing force. Background technique [0002] In my country, most areas such as Northeast, Northwest and North China have long and severe winters. The low temperature weather in winter will cause certain damage to concrete engineering, especially the concrete constructed in winter, the hydration rate is slowed down and it is extremely susceptible to freezing ice. After freezing, the porosity of concrete increases, the density decreases, the freezing pressure destroys the structure of hydration products, and the mechanical properties of concrete decrease significantly. Because the concrete surface is in direct contact with the negative temperature environment, the surface concrete cools down the fastest, and the temperature of the concrete decreases gradually from the outer layer to the inner layer....

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a method for evaluating the early freezing performance of concrete by pulling force, so as to solve the problem that it is difficult to timely and accurately evaluate the early freezing performance of negative temperature concrete due to the freezing of concrete during winter construction and the freezing damage of surface concrete is greater than that of internal concrete. Frost damage, resulting in poor quality of winter construction projects

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