【正文】 the die must be straight prestressed ponent holes for pouring concrete after the timer (15min) rotating steel pipe , handpumped tube pressure concrete surface is not significant imprint is appropriate, smoke pipe should be smooth slow。 backfill concrete form removal, timely, and to avoid the structural side of the longterm exposure. 4, the large volume basis to take the stratified subblock placement, a reasonable set of construction joints, pouring seam in the appropriate location, to speed up the heat。 附錄 B 外文文獻 On the prevention and treatment of cracks in concrete in the construction works By Asif Hameed Abstract： Concrete cracks a bad phenomenon is mon in construction projects, it directly affects the use of function and durability of concrete structures. Classification of some mon concrete cracks in the building works, and the specific circumstances of prevention and treatment measures. Keywords: concrete。采用低溫水拌制混凝土，對砂石進行冷水霧降溫，或設置簡易遮陽裝置，以降低混凝土拌合物溫度。常用的膠結(jié)材料有水泥漿、環(huán)氧樹脂、甲基丙烯酸酯、聚氨酯等化學材料。這種裂縫一般出現(xiàn)在混凝土結(jié)構(gòu)使用期間，一旦出現(xiàn)很難補救，因此應在施工中采取有效措施進行預防。五是在結(jié)構(gòu)自重不同或建筑物層高不同的相鄰部位設置后澆帶，待相鄰結(jié)構(gòu)沉降基本趨于穩(wěn)定后再澆筑。根據(jù)這些主要影響因素，人們常把混凝土裂縫歸納為收縮裂縫、溫度裂縫、沉降裂縫、徐變裂縫、應力裂縫和施工裂縫等幾大類。對于某種裂縫的出現(xiàn)，人們很難給予一個準確明晰的原因分析。在支撐底部加設墊板保證支撐牢固。八是混凝土中配置少量的小規(guī)格鋼筋或者摻入纖維材料將混凝土的溫度裂縫控制在一定的范圍之內(nèi)。 結(jié)構(gòu)加固法 當裂縫影響到混凝土結(jié)構(gòu)的性能時，就要考慮采取加固法對混凝土結(jié)構(gòu)進行處理。常用控制措施是：對加熱養(yǎng)護的構(gòu)件，應采用緩慢升降溫，使升降溫度不大于 10℃ /h，并注意緩慢揭蓋、脫模，避免表面溫度應力過大；對大體積結(jié)構(gòu)，當混凝土與外界溫差較大時，應采用保溫養(yǎng)護，適當處長拆模時間，使溫差控制在 25℃ 以內(nèi)。 施工裂縫的控制 木模板澆水濕透，防止脹模將混凝土拉裂。 cooling pipes embedded in the base, pass into the circulation of cold water, and will export the heat of hydration。 ERECTION should have a more long time, the stacking crane girder last fixed as much as possible (Creep 3 months up to 60% the basic stability of four months later, six months creep to be pleted by 70% 80%), the creep deformation in the lifting (or fixed before) most of the concrete has a longer age period, the intensity is also higher。 transport between the ponents set skids fastened with each other, to prevent shaking large ponent of the collision。 set the required temperature reinforcement in the base。 processing 1. Foreword Building construction, concrete structures, cracks, it will affect the stiffness of the concrete structures and the overall resistance of the structure of the building, even if the cracks do not lead to the destruction of concrete structures or building collapse will affect the exterior of the buildingwhen the crack width exceeds a certain limit, can also cause corrosion, durability of structural elements. This article describes several mon cracks in the concrete construction of prevention measures, control methods and cracks on the concrete construction has a certain reference value. 2. Common cracks Category Concrete cracks are many reasons, the situation is more plicated, more a bination of factors. For some cracks, it is difficult to give an accurate and clear analysis. Engineering practice shows that the main reasons for crack formation from three aspects: deformation, load, and uneven settlement. Generally by the temperature difference, shrinkage, differential settlement cracks caused by the deformation in favor of about 80% load caused about 20%, of course, also need to consider the prehensive reason. Based on these main factors, often concrete cracks summarized shrinkage cracks, temperature cracks, settlement cracks, creep cracks, stress cracks and construction cracks in several categories. 3. Common fracture analysis and prevention Plastic shrinkage cracks and prevention Plastic shrinkage of concrete in the condensation of preSurface due to excessive water loss and shrinkage. General more mon in the dry and hot and windy weather cracks, the shape of the wide in the middle, both ends of the thin, noncoherent and of varying lengths, long cracks up to 2m3m, width up to , seriously affect the resistance of concrete permeability and durability. The main preventive measures: First, make use of the shrinkage value is smaller, higher early strength portland or portland cement. Second, strict control of the watercement ratio, to minimize the amount of water to ensure the concrete construction of the required slump and workability under the premise, if necessary, mixed with superplasticizer. Third, prior to pouring concrete, grassroots and templates uniform watering wet. Timely coverage of the grip material film or wet straw mats, hemp films and so on, to keep the concrete setting the front surface moist, or sprayed on the concrete surface with the conservation agent for conservation. Subsidence cracks and prevention Subsidence cracks in the main is due to the flooding of the structure foundation, soil is uneven or not pacting the backfill caused uneven settlement due. In addition, Concrete hardening process due to the stiffness is insufficient or does not firmly support the bottom of the template will cause subsidence cracks. The main preventive measures: First, the structure of the preconstruction, to ensure the quality of ground treatment. The original foundation soil must be dense, uniform, carrying capacity and to achieve the design requirements。采取長時間養(yǎng)護，規(guī)