Summer heat, mixing plant cooling equipment to go!
Concrete is one of the most important civil engineering materials of our time. Concrete must be poured under certain temperature conditions in order to avoid later wall deformation, cracking and other conditions caused by thermal expansion and contraction. Especially in the field of large-scale construction, such as the construction of the Three Gorges Dam, Qinshan Nuclear Power Station and other projects, how to build a complete set of concrete cooling system has become the core problem faced by each project.
After concrete is poured, a large amount of heat of hydration is generated by the hydration of cement during the hardening process. Due to the large volume of concrete, a large amount of heat of hydration accumulated in the concrete and not easy to disseminate, resulting in a sharp rise in internal temperature, while the surface of the concrete heat dissipation faster, making the concrete structure inside and outside of a large temperature difference, these temperature differences caused by the internal and external thermal expansion and contraction of different degrees, so that the surface of the concrete to produce a certain degree of tensile stress. Later in the cooling process, due to the constraints of the foundation or the old concrete, tensile stresses will again appear inside the concrete. The decrease in temperature also induces significant tensile stresses at the surface of the concrete. These tensile stresses are known as temperature stresses.
Sometimes the temperature stresses can exceed the stresses induced by other external loads, and when the temperature stresses exceed the cracking capacity of the concrete, cracks will occur. Such cracks are called temperature cracks. Temperature cracks mostly occur in the late stage of concrete construction. In the construction of concrete when the temperature difference is large, or the concrete is attacked by the cold wave, etc., will lead to a sharp drop in the surface temperature of the concrete, and produce contraction, the surface contraction of the concrete by the constraints of the internal concrete, which will produce a large tensile stress and cracks, this crack is usually only in the surface of the concrete in a shallow range.
The direction of temperature cracks is usually not a certain pattern, large-area structure cracks are often crisscrossed; beams and slabs of larger length and size of the structure, the cracks are more parallel to the short side; deep and penetrating temperature cracks are generally parallel or nearly parallel to the direction of the short side, the cracks appear along the long side of the segments, and the middle of the denser. Crack width varies in size and is more obviously affected by temperature changes, wider in winter and narrower in summer. Concrete temperature cracks caused by high temperature expansion are usually thick in the middle and thin at both ends, while the thickness of cold shrinkage cracks is less obvious. The appearance of such cracks will cause corrosion of reinforcing steel, carbonization of concrete, reduce the resistance of concrete to freezing and thawing, fatigue and seepage resistance.
Li & Fung Hong's concrete cooling integrated cooling equipment adopts a cold water system to cool down and send coolness to the mixing plant! Cold water system is the most important for the whole cooling system. Through the cold water system, hot water with a temperature of over 45 degrees can be cooled down to 5 degrees Celsius, which is the best temperature for concrete activity. Lay a solid foundation for the infrastructure!