矿渣水泥抗渗结构

矿渣水泥抗渗结构水泥水化过程中产生大量的热量，每立方米砼将放 出1750027500kJ的热量，砼内部温度升高30C左右, 般在13d即释放50%以上热能。在高层建筑、桥梁、 地铁等工程中被广泛应用。但由于泵送混凝土本身的工 艺特点及施工工艺等原因，泵送砼施工的工程往往会出 现一些裂缝，其在很大程度上影响结构的抗渗和耐久性Cement hydration process produce a lot of heat, per cubic meter of concrete will emit heat of17500 27500 kj, concrete internal temperature 30C or so and - as in 1 3 d the release of more than 50% of heat energy. In high-rise buildings, Bridges, subwayandsoonarewidelyusedinengineering.But as a result of pumping concrete itself, process characteristics and construction technology of pumping concrete construction projects often appeared some cracks, largely affect the impermeability and durability of the structure.为满足泵送要求粗骨料粒径往往较小，碎石不宜大 于 1 ：3 ，卵石不宜大于 1：2.5，泵送砼的石子粒径不得 大于泵送管道直径的 1/4；为保证砼的流动性、粘聚性和 保水性及便于运输、泵送和浇筑，泵送砼的砂率要比普 通砼流动性大，约为38%45 % ;通过0. 315筛孔的砂 不应小于 15；To meet the requirements of pumping coarse aggregate size often smaller, gravel should not be greater than 1:3, pebble should not be greater than 1:2. 5, pumping concrete stones size shall not be greater than 1/4 of pumping pipe diameter; In order to ensure the liquidity of concrete, adhesiveness and water retention and facilitate transportation, pumping and pouring, pumping concrete sand ratio than ordinary concrete fluidity big, about 3 8% 3 8%; Through 0. 31 5 mesh sand shall not be less than 1 5%;有工艺简单、施工速度快、适用范围广、占用场地 小、操作便捷、大大降低劳动强度等优点，泵送砼是施 工技术进步发展而来的一项施工技术，它可一次连续完 成水平运输和垂直运输，并可连续浇筑，为保证砼具有 良好的可泵性，强度等级为 C20 C60 的砼中水泥用量一般为350550kg/m3;最小水泥用量宜为300kg/m3;Has simple process, fast construction speed, wide applicable range, small occupied space, convenient operation, greatly reduce the labor intensity, pumping concrete construction technology is progress of a construction technique, it can complete a continuous horizontal transport and vertical transport, and can continuous casting, in order to ensure the concrete has good pumpability, strength grade of C20 C60 concrete cement dosage in general is 35 0 5 5 0 kg/m3; Minimum cement dosage should be 300 kg/m3;多为高效减水剂、复合缓凝剂、引气剂等，对砼拌 和物流动性和硬化性能有影响，因而对裂缝也有影响; 大体积砼，其形成的温度应力与其结构尺寸有关。在一 定尺寸范围内，砼结构尺寸越大，温度应力也越大，因 而引起裂缝的危险性也越大。More for high efficiency water reducing agent, composite retarder, air-entraining agent, such as liquidity and hardening of concrete mixing performance have influence, therefore also have influence to crack; Big volume concrete, the formation of the temperature stress to the structure size. Within the scope of a certain size, the size of the concrete structure, the greater the temperature stress is, the greater the resulting risk of fracture.砼的干缩裂缝发生在表层很浅的位置，裂缝细微， 有时呈平行线状或网状，常常不被人们注意。但须注意 的是，干缩裂缝不仅严重损害薄壁结构的抗渗性和耐久 性，也会使大体积砼的表面裂缝发展成为更严重的裂缝， 影响结构的耐久性和承载能力。The dry shrinkage of the concrete cracks occurred in the surface layer is very shallow, subtle cracks, sometimes in parallel linear or mesh, often not to be noticed by people. But must pay attention to is that dry crack not only seriously damage the permeability resistance and durability of the thin wall, also canmake the surface of mass concrete cracks become more serious cracks, affect the structure durability and bearing capacity.大量试验研究和工程实践表明，砼中掺入一定数量 优质的粉煤灰后，不但能代替部分水泥，而且由于粉煤 灰颗粒呈球状具有滚珠效应，起到 桃苗润滑作用，可改 善砼拌和物的流动性、粘聚性和保水性，从而改善了可 泵性。砼内部的温度与砼厚度及水泥品种、用量有关。 在添加泵送剂或粉煤灰时，也可选用矿渣硅酸盐水泥。Large amount of experimental research and engineering practice show that after adding a certain amount of high quality fly ash concrete, not only can replace part of cement, and due to the effect of spherical particles of fly ash has the ball, the lubrication effect, can improve the liquidity of concrete mixing content, adhesiveness and water retention, and thus improve the pumpability. Concrete internal temperature and the thickness of concrete and cement varieties and dosage. When adding pumping agent or fly ash, also can choose slagPortland cement.另外，在行吊施工时，可充分利用砼后期强度，或 是改善骨料级配，掺加粉煤灰或高效减水剂等来减少水 泥用量，降低水化热。砼的干燥收缩受用水量的影响最 大。因此，应严格控制泵送砼的用水量，即在砼配合比 设计中，应尽可能将单方砼用水量控制在 170kg/m3 以下。Additional, when construction, can make full use of the late strength of concrete, or improve the aggregate gradation, adding fly ash and high efficient water reducing agent to reduce the dosage of cement, reduce the hydration heat. The drying shrinkage of concrete is influenced by water consumption is the largest. Pumping concrete, therefore, should strictly control the amount of water, namely in concrete proportioning design, should as far as possible will unilaterally concrete water control under 170 kg/m3.