【正文】 分離，造成嚴(yán)重后果。 5)認(rèn)真做好接漿措施，及時(shí)調(diào)整坍落度。 防水混凝土結(jié)構(gòu)施 工中，常常是底板與豎壁分別施工，即在豎壁上做施工縫處理。在澆筑豎壁時(shí)應(yīng)在接縫處先澆一層 5cm～ 10 cm厚的同標(biāo)號(hào)水 泥砂漿銜接層，以保證接縫處振搗密實(shí)。同時(shí)，隨著澆筑高度的 逐步提高，應(yīng)逐步減少用水量，減小坍落度防止?jié)仓缴喜砍霈F(xiàn) 骨料偏 少而水泥漿偏多現(xiàn)象。 施工縫作法 8 施工縫是防水結(jié)構(gòu)的薄弱環(huán)節(jié)之一。 應(yīng)盡量少留或不留，當(dāng)混凝土澆筑受到設(shè)備或支模條件的限制時(shí)，則可在征得設(shè)計(jì)單 位的同意后，在規(guī)定部位留置水平施工縫，一般留在底板以上 200 mm 處的豎壁上工程中采用新工藝 —— 膨脹性橡膠止水帶處理施工 縫的方法，取代常用方法，諸如企 口式施工縫、高低式施工縫、平 口施工縫等。防水混凝土一般在垂直方向不留置施工縫，在主樓與裙樓之 間設(shè)了后澆帶，垂直方向的施工縫在接縫部位設(shè)置膨脹性橡膠止 水帶或鋼板止水帶。由于施工縫是防水結(jié)構(gòu)的一個(gè)薄弱環(huán) 節(jié)，施工中應(yīng)專(zhuān)人負(fù)責(zé)，精心操作，確保施工質(zhì)量。采用止水鋼板時(shí)不得有漏焊，采用橡膠止水帶在接長(zhǎng)時(shí)務(wù)必要將接頭用專(zhuān)用膠水粘貼牢固可靠。 混凝土的養(yǎng)護(hù)與拆模 防水混凝土澆筑后養(yǎng)護(hù)工作的好壞，不僅影響到混凝土的強(qiáng) 度 ，而且影響到混凝土的抗?jié)B性能。試驗(yàn)證明，防水混凝土早期脫水或養(yǎng)護(hù)過(guò)程缺水 ，將大幅度降低其抗?jié)B性能。防水混凝土養(yǎng)護(hù)應(yīng)不少于 14 d防水混凝土拆模要求也比較高，拆模時(shí)間不宜過(guò)早 ，拆模時(shí) 應(yīng)精心操作，防止用鐵棍撬，大錘猛敲硬撬 ，使混凝土遭到破壞。 做好回填土 地下防水結(jié)構(gòu)的回填土是 最后一道工序，它往往被忽視，這實(shí)在是一個(gè)很大的失誤。當(dāng)構(gòu)筑物防水工作結(jié)束后應(yīng)立即進(jìn)行回填土施工。首先應(yīng)重視回填土本身的質(zhì)量；其次回填前應(yīng)清理 坑底的雜物和積水 ，回填時(shí)應(yīng)分層夯實(shí)。地下防水結(jié)構(gòu)周?chē)粚? 夯實(shí)的回填土 ，本身是一道可靠而又經(jīng)濟(jì)的防水帷幕。 在工程地下室工程施工申，由于切切實(shí)實(shí)嚴(yán)把以上七道關(guān)口，組織防水混凝土施工，效果比較理想 ，沒(méi)有出現(xiàn)滲漏水現(xiàn)象。 結(jié)束語(yǔ) 以上對(duì)混凝土的施工溫度與裂縫之間的關(guān)系進(jìn)行了理論和實(shí)踐上的初步探討，雖然學(xué)術(shù)界對(duì)于混凝土裂縫的成因和計(jì)算方法有不同的理論，但對(duì)于具體的預(yù)防 和改善措施意見(jiàn)還是比較統(tǒng)一，同時(shí)在實(shí)踐中的應(yīng)用效果也是比較好的，具體施工中要靠我們多觀察、多比較，出現(xiàn)問(wèn)題后多分析、多總結(jié)，結(jié)合多種預(yù)防處理措施，混凝土的裂縫是完全可以避免的。 9 Discuss the construction temperature and crack of the concrete lightly By G. K. Kululanga, W. Kuotcha, R. McCaffer, Member, ASCE, and F. EdumFotwe ,The American Society of Civil Engineers The summary Through observation live for many years, through consulting the monograph about stress within the concrete, explain to concrete temperature reason , onthespot concrete control and measure , prevention of crack of temperature that crack produce. Keyword: Concrete。Temperature stress。Crack 。Control 1. The concrete occupies the important position in modern engineering construction. But today, the crack of the concrete is paratively general, the cracks are nearly omnipresent in the science of bridge building. Though we take various kinds of measures in constructing, careful, but the crack still occurs now and then. Tracing it to its cause, it is one of them inpletely that our change to concrete temperature stress pays attention to. In the large volume concrete, temperature stress and temperature control are significant. This is mainly because of the reason of two respects. First of all, concrete often appear the temperature crack in not constructing, influence the globality and durability of the structure. Secondly, in the course of operating, the temperature change has remarkable influence that can39。t be ignored on the stress state of the structure. We meet to construct temperature crack in mainly, so only to origin cause of formation and treatment measure, concrete of crack make a discussion in constructing this text. Reason of a crack 10 Have many kinds of reasons to produce the crack in the concrete, it is mainly the changes of temperature and humidity, fragility and disparity of the concrete, and the structure is unreasonable, the raw materials is not up to standard (if the alkali aggregate react), the template is out of shape, the foundation does not subside etc. evenly . The cement emits a large amount of heat of hydration when the concrete is hardenned, inside temperature is rising constantly, cause the stress of drawing on the surface. In the course of lowering the temperature , is it congeal foundation pay restrain to mix always later stage, will present the stress of drawing within the concrete . Reducing of temperature can surface cause heavy stress of drawing very in concrete too. When these draw the stress and go beyond resisting the ability of splitting of concrete , namely will present the crack . A lot of inside humidity of concrete change very light or change relatively slow, surface humidity might change heavy the violent change takes placing. Such as maintaining thoroughly, when getting wetter when not doing,contract surface there aren39。t deformation doing, often cause the crack too. The concrete is a kind of fragility material , tensile strength is about 1/10 of the pression strength, is it carry on one39。s shoulder or back limit when draw out of shape to have *104 only , is it carry on one39。s shoulder or back limit location when stretch out of shape to there is *104 to add for a long time to add a short time. Because raw materials even, water dust than unstable, transport and build phenomenon of emanating of course, its tensile strength is not even in the same concrete, a lot of resist the ability of drawing very low, it is apt to present the weak position of the crack. Among armored concrete , draw stress to undertake by reinforcing bar mainly , concrete bear stress of keeping just. Or reinforcing bar mix if edge position gone to to congeal present the stress of drawing in the structure in plain concrete, must rely on the concrete oneself to bear . Require to avoid the stress of drawing or only very small stress of drawing appears of the the general design. But 11 the concrete is cooled from maximum temperature to the steady temperature of operating period in constructing, often cause sizable to draw the stress within the concrete. The temperature stress can exceed other outsides and load the stresses caused sometimes, know change law , temperature of stress for carry on reasonable structural design and construct extremely important. Analysis of 2 temperature stresses Can be divided into following three stages according to the forming process of the temperature stress: (1)It is early: Build concrete is it is it over basically to send out heat to cement to begin , generally one one day by oneself. Two characteristics at this stage, first, the cement emits a large amount of heat of hydration, second , mix and congeal the changing sharply of elastic model quantity. Because of the change of elastic model quantity , form the remaining stress in the concrete in this period. (2)Middle period: Up til