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通过实地调研发现,新疆南疆盐渍土地区许多混凝土建(构)筑物均不同程度地存在由盐蚀-冻融引起的混凝土表面剥蚀、开裂和酥松、粗骨料大面积裸露、盐结晶析出等病害。引起该地区混凝土产生盐蚀-冻融病害的主要原因有3个方面:1混凝土表层和内部的孔隙水冻结产生的膨胀拉应力;2渗入混凝土内部的盐类结晶产生的结晶拉应力;3硫酸盐与水泥水化产物发生化学反应产生的膨胀拉应力。这些因素综合作用造成混凝土由表及里逐渐损伤、破坏和解体。通过调整混凝土水胶比、优化含气量和搅拌时间、优选骨料、使用抗硫酸盐水泥、增厚混凝土表面沥青胶泥防腐涂层厚度等工程措施,可有效提升南疆盐渍土地区混凝土结构抵抗盐蚀和冻融破坏的能力。
Through field investigation, it is found that many concrete structures in saline soil area of southern Xinjiang have denudation, cracking and crispiness of concrete surface caused by salt-eroded-freeze-thawed structures to varying extents. Large areas of coarse aggregate are exposed and salt crystals Precipitation and other diseases. The main causes of salt-freeze-thaw damage in concrete in this area are as follows: 1 Expansion tensile stress caused by the freezing of pore water in the concrete surface and the interior; 2 Crystallization tensile stress caused by salt crystals infiltrated into concrete; 3 Sulfuric acid Salt and cement hydration products produced by the chemical reaction of tensile stress. The combined effect of these factors causes the concrete to gradually be damaged, destroyed and disintegrated from the surface. By adjusting the water-cement ratio of concrete, optimizing gas content and mixing time, optimizing aggregates, using sulfate-resistant cement and thickening the thickness of anticorrosive coating of asphalt cement on concrete surface, the structural resistance of concrete in saline soil area of southern Xinjiang can be effectively improved Salt and freeze-thaw damage ability.