1, basement roof waterproofing The basement roof mentioned here refers to the part of the roof without buildings. Often hidden by backfill soil, outdoor square bricks or flower beds, it not only bears the load of vehicles and pedestrians, but also experiences wind, frost, rain and snow, so its waterproof is particularly important.
The basement roof is generally poured with waterproof concrete with the same strength grade and permeability grade as the bottom plate and external wall. An important means to test the self-waterproof ability of concrete is to carry out water storage test, but the self-waterproof test of basement roof is often not paid enough attention in design and construction. It is particularly noteworthy that some basements are equipped with anti-beams, which will form a roof "pool" when it rains. In order to ensure that the basement is watertight, this part of the roof should be waterproof in detail.
1. 1 When testing water, the basement roof should be tested with reference to the basement exterior wall, especially the roof with lintel, which can not be ignored, and the leakage parts should be reinforced and repaired in time. The water storage test can be carried out in sections according to the construction needs, but it must be ensured that all the roofs of this part are inspected.
1.2 waterproof layer construction: After testing the water to fill the leak in the basement roof, start the waterproof layer construction. The basement roof should be made of flexible materials, and the protective layer should be set with cement mortar or fine stone concrete. In construction management, waterproof layer construction, protective layer setting and backfilling should be carried out continuously to reduce and avoid damage to waterproof layer and protective layer.
1.3 slope adjustment When looking for the basement roof, the slope should be ||| large and become a certain slope, so that rainwater will not accumulate on the roof. When the basement roof is equipped with anti-beam, drainage holes should be reserved in advance.
2. In the construction of post-pouring belt in basement, there are two noticeable problems: waterproofing of post-pouring belt and formwork support.
2. 1 Waterproofing of post-cast strip In many projects, the design requirements of post-cast strip must be closed when the structure is capped or even later, so the post-cast strip must be waterproof before it is closed. Please refer to the general building standard design of Central and South China (88ZJ3 1 1) for the common waterproof practices of post-poured strip in Central and South China. In actual construction, corresponding adjustments should be made according to different projects.
2. 1. 1 Waterproof treatment of foundation beam The waterproof treatment of foundation beam before the closure of post-cast strip should constitute a whole, so the waterproof treatment of foundation beam at post-cast strip should be arranged in advance and cannot be omitted. For the convenience of construction, the side formwork of this part of the foundation beam should adopt brick formwork, which should be leveled and waterproof. The bottom of the beam can refer to the waterproof treatment of post-cast strip at the bottom.
2. 1.2 concrete cushion of post-cast strip
There are many measures to prevent the sudden surge of groundwater. If the project adopts the dewatering method, the concrete cushion construction at the post-pouring zone should take into account that when the post-pouring zone is not closed, the dewatering will be reduced or even stopped due to factors such as basement construction, so the cushion should be strengthened. Such as thickening, improving concrete strength grade, reinforcement and other measures to prevent sudden surge. The thickness and reinforcement of concrete cushion can be calculated and determined according to the width of post-pouring zone and groundwater pressure.
2. 1.3 waterproofing of external wall post-cast strip adopts 88ZJ3 1 1 waterproofing method. Due to the influence of formwork support and concrete pouring, the retaining wall and waterproof layer are easily damaged in construction.
2.2 when the template of post-cast strip is retained, the template support on both sides of post-cast strip should be firm and tight, and easy to dismantle or use at one time. The use of disposable single-layer steel mesh often causes concrete and concrete slurry to flow into the post-pouring zone, which is difficult to clean. The following methods can be adopted in the construction: make a negative dam with a width of about 5cm at the formwork support with waterproof cement mortar under the bottom reinforcement of the beam slab to avoid concrete pouring into the post-cast strip from below the bottom reinforcement. For deep, thick and difficult-to-clean beams and slabs, double-layer nets are used as one-time templates, one layer of steel mesh and the other layer of fine-mesh barbed wire, and the two layers of nets can be tied and fixed together in advance. The double-layer net is supported by shaped steel bars and fixed by welding bottom bars and gluten. If conditions permit, you can also use a disposable template, such as a quick and simple closing net.