【正文】 he anti jelly which lower concrete melt, anti tired and anti Shen ability etc.. Main prevention measure:One is as far as possible choose to use low hot or medium hot water mire, like mineral residue cement, powder ash from stove cement...etc..Two is a decrease cement dosage, cement dosage as far as possible the control is in the 450 kg/m 3 is to lower water ash ratio, water ash of the general concrete ratio control below is improvement the bone anticipate class to go together with, the Chan add powder ash from stove or efficiently reduce water etc. to e to reduce cement dosage and lower water to turn is an improvement concrete of mix blend to process a craft, lower sprinkle of concrete to build is the in addition that the Chan add a have of fixed amount to reduce water and increase Su, slow Ning etc. function in the concrete, improvement the concrete mix to match a thing of mobility, protect water, lower water to turn hot, postpone hot Feng of emergence is the heat season sprinkle to build can the adoption take to establish to hide sun plank etc. assistance measure control concrete of Wen Sheng, lower to sprinkle temperature of build the is the temperature of big physical volume concrete should the dint relate to structure size, concrete structure size more big, temperature should dint more big, so want reasonable arrangement construction work preface, layering, cent the piece sprinkle to build, for the convenience of in spread hot, let up is at great inner part constitution of the physical volume concrete cool off piping, cold water perhaps cold air cool off, let up concrete of inside outside difference in is the supervision which strengthen concrete temperature, adopt to cool off in time, protection is to reserve temperature constringency to is to let up to control, sprinkle proper before building concrete in the Ji rock and old concrete top build a 5 mm or so sand mat a layer or usage asphalt etc. material Tu2 is to strengthen concrete to protect, the concrete after sprinkle build use moist grass Lian in time, hemp slice39。s45 176。t big in match ratio design give settle of use water is the earlier period which strengthen concrete to protect, and appropriate extension protect of concrete construction want to be appropriate extension concrete heat preservation to overlay time, and Tu2 Shua protect to is a constitution the acmodation is in the concrete structure of the constringency sew. Su constringency crack and prevention Su constringency is the concrete is before condense, surface because of lose water quicker but creation of Su constringency crack is general at dry heat or strong wind the weather appear, crack39。Have outside carry the crack that the function cause。 出自《加拿大土木工程學(xué)報》附件2：外文原文（復(fù)印件）Building construction concrete crack ofprevention and processingAbstractThe crack problem of concrete is a widespread existence but again difficult in solve of engineering actual problem, this text carried on a study analysis to a little bit familiar crack problem in the concrete engineering, and aim at concrete the circumstance put forward some prevention, processing measure. Keyword:Concrete crack prevention processingForeword Concrete39。通常的預(yù)防措施有：一是保證鋼筋保護層的厚度。主要的預(yù)防措施：一是選用堿活性小的砂石骨料。十四是混凝土中配置少量的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)。十一是預(yù)留溫度收縮縫。七是高溫季節(jié)澆筑時可以采用搭設(shè)遮陽板等輔助措施控制混凝土的溫升，降低澆筑混凝土的溫度。三是降低水灰比。高溫膨脹引起的混凝土溫度裂縫是通常中間粗兩端細，而冷縮裂縫的粗細變化不太明顯。當(dāng)拉應(yīng)力超過混凝土的抗拉強度極限時，混凝土表面就會產(chǎn)生裂縫，這種裂縫多發(fā)生在混凝土施工中后期。五是在凍土上搭設(shè)模板時要注意采取一定的預(yù)防措施?！　≈饕A(yù)防措施：一是對松軟土、回填土地基在上部結(jié)構(gòu)施工前應(yīng)進行必要的夯實和加固。45176。四是及時覆蓋塑料薄膜或者潮濕的草墊、麻片等，保持混凝土終凝前表面濕潤，或者在混凝土表面噴灑養(yǎng)護劑等進行養(yǎng)護。影響混凝土塑性收縮開裂的主要因素有水灰比、混凝土的凝結(jié)時間、環(huán)境溫度、風(fēng)速、相對濕度等等。五是在混凝土結(jié)構(gòu)中設(shè)置合適的收縮縫。二是混凝土的干縮受水灰比的影響較大，水灰比越大，干縮越大，因此在混凝土配合比設(shè)計中應(yīng)盡量控制好水灰比的選用，同時摻加合適的減水劑。干縮裂縫多為表面性的平行線狀或網(wǎng)狀淺細裂縫，大體積混凝土中平面部位多見，較薄的梁板中多沿其短向分布?！　』炷凉こ讨谐Ｒ娏芽p及預(yù)防:　　　　干縮裂縫多出現(xiàn)在混凝土養(yǎng)護結(jié)束后的一段時間或是混凝土澆筑完畢后的一周左右。鋼筋混凝土規(guī)范也明確規(guī)定：有些結(jié)構(gòu)在所處的不同條件下，允許存在一定寬度的裂縫。但是在混凝土受到荷載、溫差等作用之后，微裂縫就會不斷的擴展和連通，最終形成我們?nèi)庋劭梢姷暮暧^裂縫，也就是混凝土工程中常說的裂縫。附件1：外文資