【正文】 t be too early, and want to notice to dismantle a mold order of is at jelly soil top take to establish template to notice to adopt certain of prevention measure. Temperature crack and prevention Temperature crack much the occurrence is in big surface or difference in temperature variety of the physical volume concrete pare the earth area of the concrete structure. Concrete after sprinkling to build, in the hardening the process, cement water turn a creation a great deal of of water turn hot, .(be the cement dosage is in the 350550 kg/m 3, each sign square the rice concrete will release a calories of 1750027500 kJ and make concrete internal thus the temperature rise to reach to 70 ℃ or so even higher)Because the physical volume of concrete be more big, a great deal of of water turn hot accumulate at the concrete inner part but not easy send forth, cause inner part the temperature hoick, but the concrete surface spread hot more quick, so formation inside outside of bigger difference in temperature, the bigger difference in temperature result in inner part and exterior hot the degree of the bulge cold Suo dissimilarity, make concrete surface creation certain of pull should pull should dint exceed the anti of concrete pull strength extreme limit, concrete surface meeting creation crack, this kind of crack much occurrence after the concrete under construction the concrete of under construction be difference in temperature variety more big, perhaps is a concrete to be subjected to assault of cold wave 浙江大學城市學院畢業(yè)設計 外文翻譯 etc., will cause concrete surface the temperature sharply descend, but creation constringency, surface constringency of the concrete be subjected to inner part concrete of control, creation very big of pull should dint but creation crack, this kind of crack usually just in more shallow scope of the concrete surface creation. The alignment of the temperature crack usually none settle regulation, big area structure the crack often maneuver interleave。二是混凝土級配要良好。八是大體積混凝土的溫度應力與結構尺寸相關，混凝土結構尺寸越大，溫度應力越大，因此要合理安排施工工序，分層、分塊澆筑，以利于散熱，減小約束。 溫度裂縫及預防 溫度裂縫多發(fā)生在大體積混凝土表面或溫差變化較大地區(qū)的混凝土結構中。 主要預防措施：一是選用干縮值較 小早期強度較高的硅酸鹽或普通硅酸鹽水泥。水泥漿中水分不斷的蒸發(fā)會產生干縮現象，且這種收縮是不可恢復 的。由于混凝土施工和自身 變形、約束等一系列 的問題，硬化成型的混凝土中存在許 多的微小孔隙、氣孔和微裂縫， 由于這些初始缺陷的存在才使 得 混凝土呈現出一些非均質的特性。混凝土干縮主要和混凝土的水灰比、水泥的成分、水泥的用 量、集料的性質和用量、外加劑的用量等有關。 沉陷裂縫及預防 沉陷裂縫的產生 是由于結構地基土質 不均勻、松軟、 回填土不實或浸水而造成不均勻沉降所致；或者因為模板剛度不足，模板支撐間距過大或支撐底部松動等導致，特別是在冬季，模板支撐在凍土上，凍土化凍后產生不均勻沉降，致使混凝土結構產生裂縫。 溫度裂縫的走向通常無一定規(guī)律，大面積結構裂縫常縱橫交錯；梁板類長度尺寸浙江大學城市學院畢業(yè)設計 外文翻譯 較大的結構，裂縫多平行于短邊；深入和貫穿性的溫度裂縫一般與短邊方向平行或接近平行，裂縫沿著長邊分段出現，中間較密。十三是加強混凝土養(yǎng)護，混凝土澆筑后，及時用濕潤的草簾、麻片等覆蓋，并注意灑水養(yǎng)護，適當延長養(yǎng)護時間，保證混凝土表面緩慢冷卻。t appear crack possibly or as 浙江大學城市學院畢業(yè)設計 外文翻譯 far as possible decrease crack of amount and width, particularly want to as far as possible avoid harmful crack of emergence, insure engineering quality thus. Concrete crack creation of the reason be a lot of and have already transformed to cause of crack:Such as temperature variety, constringency, inflation, the asymmetry sink to sink etc. reason cause of crack。t have the surface crack of influence and deep enter crack of processing measure that is usually is a surface in crack daubery cement syrup, the wreath oxygen gum mire or at concrete surface Tu2 Shua paint, asphalt etc. antisepsis material, at protection of in the meantime for keeping concrete from continue under the influence of various function to open crack, usually can adoption the surface in crack glue to stick glass fiber cloth etc. measure. Infuse syrup, the Qian sew method Infuse a syrup method main the concrete crack been applicable to have influence or have already defend Shen request to the structure whole of repair, it is make use of pressure equipments gum knot the material press into the crack of concrete, gum knot the material harden behind and concrete formation one be whole, thus reinforce of in mon use gum knot material has the cement the syrup, epoxy, A Ji C Xi sour ester and gather ammonia ester to equalize to learn material. The Qian sew a method is that the crack be a kind of most in mon use method in, it usually is follow the crack dig slot, the Qian fill Su in the slot or rigid water material with attain closing crack of in mon use Su material has PVC gum mire, plastics ointment, the D Ji rubber etc.。s much presenting in the center breadth, both ends be in the centerthin and the length be different, with each other not coherent crack general long 2030 cm, the longer crack can reach to a 23 m, breadth 15 creation of main reason is:The concrete is eventually almost having no strength or strength before the Ning very small, perhaps concrete just eventually Ning but strength very hour, be subjected to heat or pare strong wind dint of influence, the concrete surface lose water to lead quick, result in in the capillary creation bigger negative press but make a concrete physical volume sharply constringency, but at this time the strength of concrete again can39。主要的預防措施：一是選用堿活性小的砂石骨料。三是降低水灰比，一般混凝土的水灰比控制在 以下。 主要預防措施：一是對松軟土、回填土地基在上部結構施工前應進行必 要的夯實和加固。五是在混凝土結構中設置合適 的收縮縫。鋼筋混凝土規(guī)范 明文規(guī)定：不同結構在不同的所處條件下 ，允許存在一定寬度的裂縫。近代科學研究和大量的混凝土工程實踐證明，在混凝 土工程中裂縫問題是不可避免的，在一