Method for cooling mass concrete

Abstract

The invention provides a method for cooling mass concrete, comprising the following steps of: 1) arranging a two-layer water pipe; 2) melting a phase-change material into a liquid state and injecting the phase-change material into an outer-layer pipe of the two-layer water pipe, blocking a water outlet end of the outer-layer pipe, standing and cooling the two-layer water pipe; 3) pouring concrete slurry to an engineering position and vibrating; 4) continuously injecting cooling water into an inner-layer pipe of the two-layer water pipe, and monitoring the temperature of the cooling water which flows out of a water outlet end; 5) after the mass concrete is cooled, liquidizing the phase-change material and draining the phase-change material through the outer-layer pipe, and drawing out the inner-layer pipe simultaneously; and 6) preparing cement paste, and pouring the cement paste into the outer-layer pipe. According to the method provided by the invention, the temperature of the phase-change material in the phase-change temperature range is quite stable, so that the temperature of the outer-layer pipe of the two-layer water pipe is stable, and the temperature difference between the outer-layer pipe and the concrete is not big, therefore a lot of cold-contraction micro cracks are prevented; and by the adoption of the phase-change material, the cooling speed of the concrete is effectively reduced, and the temperature difference between inside and outside of the concrete is reduced, therefore the generation of temperature cracks is prevented.

Description

technical field [0001] The invention belongs to the technical field of building materials, and in particular relates to a cooling method for large-volume concrete. Background technique [0002] After mass concrete is poured, the heat of hydration of the cement will lead to a significant increase in the internal temperature of the concrete. The maximum temperature can usually reach 60-80°C, and sometimes even exceed 90°C. The compressive stress is generated inside the concrete, and the tensile stress is generated outside. However, the elastic modulus and tensile strength of the concrete in the early stage are very low, so the concrete surface is prone to cracks. During the curing and cooling period, the internal temperature of the concrete drops to produce shrinkage deformation, but the deformation is affected by the foundation or other constraints, resulting in the generation of internal cracks. [0003] In the process of mass concrete construction, in order to prevent the ...

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Problems solved by technology

[0006] 1) Direct mixing of phase change materials: This method is simple, but the solid-liquid phase change materials will generate liquid phase during use, and produce volume expansion, which will lead to the destruction of building matrix materials. At the same time, some phase change materials Also corrosive to building substrates

[0007] 2) Preparation of shaped phase-change composite materials: composite phase-change materials and carriers, encapsulate the phase-change materials inside the carrier, and prepare shaped phase-change composite materials, mainly including microencapsulation, porous material adsorption method, and melt blending method 3 methods, although these methods have overcome or alleviated the negative impact of solid-liquid phase change materials in the phase change process to a certain extent, but there are also complex preparation processes, low encapsulation efficiency, and low utilization of phase change materials ( Only two phase transitions have occurred (one solid-liquid phase transition and one liquid-solid phase transition), the amount of phase change material added is limited, and the phase change enthalpy is not enough.

However, this method ignores that when the ambient temperature is not in the phase change range, the phase change material does not undergo phase change to absorb heat, which makes this method use cooling water to cool down the hydration temperature rise of mass concrete, only in the mass concrete When the temperature reaches the phase change range of the phase change material, the heat absorption capacity of the cooling water will increase significantly, but when the temperature of the concrete is lower than or exceeds the phase change range, the heat absorption capacity of the cooling water will be significantly reduced, and the temperature of the concrete will rise soon

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