With the development of underground space and the use of the increasingly common, more and more underground works, but also accompanied by some problems. For example, the Basement Insulation area is large, the volume is large, because the concrete cracks lead to the phenomenon of leakage of water seriously, and even affect the use of buildings and structural safety. The following with the actual project supervision, the Basement Insulation of concrete construction problems prone to a brief analysis.
1, the Basement Insulation of concrete strength is high, easy to make the structure of a serious shrinkage cracks.
In the design, the design of high-rise buildings, the general strength of concrete design column, taking into account the construction and other factors, often the Basement Insulation of the concrete wall strength is equivalent to the column concrete strength. General board wall concrete strength should not be greater than C40. In the construction, the original design of concrete strength is high, and the construction of concrete mix ratio is not easy to control, the actual pouring of concrete strength is often much higher than the design strength, which is likely to lead to concrete due to high strength and shrinkage cracks.
2, after pouring with pouring time control is insufficient, causing structural settlement cracks.
Generally, the pouring zone is divided into two types: one is the extensible post-pouring belt which is set up for the long structure, and the other is the settling post-pouring zone which prevents the uneven settlement. In the actual project, some designers did not clear, and the construction workers do not pay attention to the settlement after pouring with the expansion of pouring with the confused, and pouring together. In this way, it is possible to produce structural subsidence cracks. Generally, the pouring time of the pouring belt is about two months, and the pouring time of the pouring belt is the main structure, and the observation data is determined according to the settlement observation data.
3, after pouring with no strengthening and protection measures, there is a greater quality and safety risks.
1) The post-pouring part of the beam plate reinforcement is not strengthened and protected. After the post-pouring belt for the second post-pouring,Basement Insulation pouring after the formation of the site prone to stress concentration, if the reinforcement does not take measures to strengthen the structure of the concrete will produce a greater tensile stress, resulting in concrete cracks later. In addition, some construction companies do not pay attention to protection, making the post-pouring belt within the long-term exposure to moisture or soaked in water, resulting in corrosion of steel and affect its adhesion and effective cross-section.
2) prematurely remove the bottom of the posture with the bottom of the template support. Some of the construction unit to the rear part of the components as a cantilever beam, its strength reached 100% after the bottom of the template to remove the support, and even in the upper part of the template to support or stacking materials, this approach is very dangerous, Easy to cause cracks in the upper part of the component and even collapse. After the pouring beam plate is not cantilevered components, the bottom of the template support must be poured with concrete pouring completed and reached the required strength before removal. For the sake of convenience, it is suggested that the template support of the post-pouring zone be erected as a separate support system that is disengaged from the periphery.