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Concrete structure from the waterproof, is the density of the project itself to achieve waterproof function of a waterproof approach. Engineering self-waterproof structure is usually used C30.P8 waterproof concrete, admixture in the general selection of PNC concrete early strength expansive agent. PNC is a calcium aluminum sulphoaluminate concrete expansion agent, in addition to a swelling function, the concrete is also a significant early strength, enhanced, low temperature hardening, impermeability, frost damage, resistance to sulfate and other properties. PNC added to the cement concrete, the formation of the expansion of crystalline hydrates - hydrated calcium sulphoaluminate,{-File.GetString-|-D:\zp\roadroutercrack2\1.txt-|-0-0-|-true- the expansion of concrete, dense structure. In the constrained conditions of expansion, the expansion of the generated energy can be converted into compressive stress, the compressive stress 0.2-0.7Mpa, can eliminate or partially offset the concrete shrinkage, creep, temperature and other tensile stress, which can prevent concrete Of the shrinkage cracking. The ettringite crystal has the function of filling and cutting the capillary pores of the concrete, which can significantly improve the early strength, late strength and impermeability of concrete. The optimal dosage of PNC should be determined according to the requirements of the project and the cement selected. Generally, the content of compensated contraction should be 10-15%, and the content of filled concrete should be 15-20%. Mixing design and the same as ordinary concrete, feeding procedures and ordinary concrete the same. PNC dosage to produce special tools, personal responsibility, the error should be less than 0.5%.
The materials used for waterproof concrete shall meet the following requirements:
① cement varieties should be selected according to design requirements, the strength level should not be less than 32.5, shall not use expired or damp agglomerated cement. The amount of cement should not be less than 300Kg / m3; ② gravel or gravel size should be 5 ~ 40mm, mud content shall not exceed 1.0%,{-File.GetString-|-D:\zp\roadroutercrack2\1.txt-|-0-0-|-true- mud content shall not exceed 0.5%; ③ sand is appropriate in the sand, mud content shall not exceed 3.0%, mud content shall not exceed 1.0%; ④ mixed with concrete water, should be used without harmful substances in clean water; ⑤ additive technical performance, should be consistent with national or industry standards First-class products and above the quality requirements; ⑥ The level of fly ash should not be less than 2, the content should not be greater than 20%; silicon powder content should not exceed 3%, other admixtures should be determined by experiment.
Waterproof concrete must be used high-frequency mechanical vibrator dense, vibrating time to the concrete and do not take the bubbling Pan prevail, to avoid leakage, under vibration and super-vibration. After pouring concrete, should be conservation, timely coverage with straw mat. Concrete hardening,{-File.GetString-|-D:\zp\roadroutercrack2\1.txt-|-0-0-|-true- there must be someone responsible for the conservation, conservation time of not less than 14 days, such as the emergence of honeycomb holes, loose areas can be removed, and carefully processed, and then mixed with PNC mortar or fine stone concrete repair.
 
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