1、 第9页Analyzes the reinforced concrete quality questionOne.，.Ma concrete surfacePhenomenon : the lack of concrete slurry local surface roughness, or a number of small pits, but without the exposed steel and rubble. Analysis : 1 .template or cleaning the surface roughness is not clean, dry sticky with
2、cement mortar and other debris, demolding when concrete surface sticky loss. 2, the steel template Release Agent Brushing uneven concrete surface when demolding Bond template. 3, the joint assembly template is not tight, seamless when reperfusion concrete slurry leak. 4, non-compacting concrete vibr
3、ated, the concrete bubble not emits bubbles remain part of the template surface. Preventive measures : clean up the template surface, it may not sticky dry cement mortar, and other debris. Concrete Formwork reperfusion wood, with copious full moist, clean, leaving no water, seamless mosaic template
4、closely and, if cracks, Yan filled to prevent leakage pulp. Tu-steel template for applying a uniform should not brush missed. Concrete must be uniform code compaction density stratification, and to prevent leakage pound, the typical uniform concrete vibrated to remove air bubbles date. Treatment Met
5、hods : Ma main concrete surface appearance, for the larger part of the patch. Ma site will soon face wash with water, after the full use of humid wet cement disappearing. Two, cellular Phenomenon : concrete local Susong, small stone mortar, the gap between the gravel to form honeycomb of holes. Anal
6、ysis : 1, unreasonable mix concrete, aggregates, cement materials measurement errors, or no increase in water, resulting in fewer stone mortar more. 2, concrete mixing time is short, there is no uniform mixing, concrete workability poor, vibration compaction. 3, the absence of rules to pouring concr
7、ete, cutting misconduct, gravel concentrate, causing concrete disintegrate. 4, a concrete cutting too much, not above, stratified perfusion, vibration or under false information and vibrated with bad, - not allowed under vibration also expected. 5, no template pore blocking good, or template insuffi
8、cient stability, vibration at the concrete formwork shift, resulting in serious leakage pulp. Prevention measures : concrete batching strict control than with regular checks ensure accurate measurement of material (use of electronic automatic measurement). Concrete Mixing uniformity, color consisten
9、cy, stirring with the shortest time with regulations. Concrete free dumping charged no more than 2m high, in excess, to take series cones chute cutting measures. Concrete stamping layered vibration, casting layer thickness not exceeding vibrator role of the length of 1.25 times. Ramming concrete mix
10、ture, plug-Tamper little distance between its mobile role radius of 1.5 times; of fine aggregate concrete mixture, the effect is not greater than the radius of 1%. Tamper template to the distance of not more than Tamper effective radius of the half. To ensure the upper and lower concrete with good v
11、ibrating rods inserted 5cm lower concrete, concrete vibrated, must master each time point vibration. Suitable vibration phenomena : Concrete not significantly subsided and no longer appear bubble. Pouring concrete, it is often observed template, template found walking to immediately stop pouring, an
12、d the initial setting of concrete before finishing well. Governance : a small concrete honeycomb, first wash with water clean, and 1:2 or 1:2.5 with cement mortar to repair If large honeycomb, the first of gravel and loose particles removed outstanding, in an attempt to form trumpet, foreign export,
13、 more Then rinse well with water humid, and then a high fine stone concrete Ramming, strengthen conservation. Three, openings Phenomenon : concrete structure within the gap, no local concrete. Analysis : 1, the steel-intensive or embedded parts, concrete pouring not smooth and not full template spac
14、e.2, failure to order vibrated concrete, have missed vibration. 3, concrete disintegrate, or serious run slurry. 4, Concrete Construction works well, the absence of the construction sequence and Construction Technology serious operation. 5, a mass of concrete and debris incorporation, or large piece
15、s of wood and other materials into the concrete with China. 6, as required under material, a material under excessive vibration due to the lower vibration role radius of less than form a loose state. Preventive measures : 1, the steel-intensive, use small stone pouring concrete, concrete space fille
16、d with templates, and seriously vibration compacting. Mechanical vibration difficulties, the use of artificial tamper with. 2, reserved holes at the same time cutting both sides. Often dissatisfied with the lower perfusion, the vibration is not to take side in the opening perfusion measures vibratio
17、n compacting closure after good template, Then up reperfusion.3, proper compaction methods to prevent leakage vibration. A. Plug-Tamper vertical vibration, that is vibrating rods and concrete vertical or inclined surface vibration. that is vibrating rods and concrete surface of a certain point, arou
18、nd 40 -45 . B. Tamper with interpolation points uniform, it is determinant or staggered sequence of movement, not mix to avoid leakage vibration. Each moving distance of not more than vibrating rod role of the radius of 1.5 times. Tamper operation slowly pulling fast Chap. 4, under good control info
19、rmation. To ensure that concrete reperfusion not have segregation, concrete dumping free-less than 2m in height, but when more than 2m chute, Series extinguishers blanking.5, preventing sand, stones mixed with clay blocks or ice, and other miscellaneous items, have found concrete debris, timely clea
20、nse. 6, strengthening construction technology management and quality inspection. Concrete holes on the handling by the unit to jointly research, develop reinforcement program for approval before processing four, the exposed bar Phenomenon : reinforced concrete structure revealed that the steel bars
21、in concrete surface. Analysis : 1, pouring concrete vibrated, the steel pan or pan displacement of missing or too little, bar close template. 2, reinforced concrete structure with less dense steel, as a large diameter steel stuck in gravel, Concrete can not be filled with cement reinforced around. 3
22、, Mix Concrete misconduct have segregation, or template serious leak plasma. 4, the concrete vibrated, the vibrating steel rods impact, reinforced shift. 5, concrete protective layer vibration compaction, or template humid enough wood, concrete surface excessive water loss, or knock out prematurely.
23、 demolding when concrete na Prism swap Kok. Preventive measures : 1, infusion of concrete, steel reinforcement and inspection protective layer thickness accuracy. 2, in order to guarantee the concrete protection of the layer thickness, and fixed to pan. General about every 1m tied up in a reinforced
24、 cement mortar pan. 3, bar more intensive, matching appropriate size of gravel. The largest size stone structure section shall not exceed one-fourth of the minimum size, but not larger than three-quarters of reinforced distance. Structure section is smaller, more closely reinforced when available Fi
25、ne Stone Concrete Pouring. 4, reinforced to prevent displacement, no vibrating steel rods impact. 5, concrete freedom charged with more than 2m, with series such as tube or chute for the next information. 6, demolding time according to specimen test results to prevent premature demolding. 7, the ope
26、ration should not stampede steel reinforced as a hit bends or release, the timely transfer directly complement the deduction. Treatment : exposed reinforced concrete residue on the rust and clean up the water washing humid, and then 1:2 or 1 : 2.5 Mortar TROWELING formation, as revealed deep tendons
27、 of weak concrete removed, washed away humid, with a high fine stone concrete Ramming, conservation seriously. 解析钢筋混凝土质量问题一、砼麻面现象：砼表面局部缺浆粗糙，或有许多小凹坑，但无钢筋和碎石外露。原因分析：1、模板表面粗糙或清理不干净，粘有干硬水泥砂浆等杂物，拆模时砼表面被粘损。2、钢模板脱模剂涂刷不均匀，拆模时砼表面粘结模板。3、模板接缝拼装不严密，灌注砼时缝隙漏浆。4、砼振捣不密实，砼中的气泡未排出，一部分气泡停留在模板表面。预防措施：模板面清理干净，不得粘有干硬水泥砂浆
28、等杂物。木模板灌注砼前，用清水充分湿润，清洗干净，不留积水，使模板缝隙拼接严密，如有缝隙，填严，防止漏浆。钢模板涂模剂要涂刷均匀，不得漏刷。砼必须按操作规程分层均匀振捣密实，严防漏捣，每层砼均匀振捣至气泡排除为止。处理方法：麻面主要影响砼外观，对于面积较大的部位修补。即将麻面部位用清水刷洗，充分湿润后用潮湿的水泥抹平。 二、蜂窝现象：砼局部酥松，砂浆少碎石多，碎石之间出现空隙，形成蜂窝状的孔洞。原因分析：1、砼配合比不合理，碎石、水泥材料计量错误，或加水量不准，造成砂浆少碎石多。2、砼搅拌时间短，没有拌合均匀，砼和易性差，振捣不密实。3、未按操作规程浇注砼，下料不当，使碎石集中，造成砼离析。4
29、、砼一次下料过多，没有分段、分层灌注，振捣不实或下料与振捣配合不好，未允分振捣又下料。5、模板孔隙未堵好，或模板稳定性不足，振捣砼时模板移位，造成严重漏浆。预防措施：砼配料时严格控制配合比，经常检查，保证材料计量准确（可采用电子自动计量）。砼拌合均匀，颜色一致，其搅拌最短时间符合规范规定。砼自由倾落高度不得超过2m，如超过，要采取串筒、溜槽等措施下料。砼的振捣分层捣固，浇注层的厚度不得超过振动器作用部分长度的1.25倍。捣实砼拌合物时，插入式振捣器移动间距不大于其作用半径的1.5倍；对细骨料砼拌合物，则不大于其作用半径的1倍。振捣器至模板的距离不大于振捣器有效作用半径的1/2。为保证上下层砼结
30、合良好，振捣棒插入下层砼5cm，砼振捣时，必须掌握好每点的振捣时间。合适的振捣现象为：砼不再显著下沉，不再出现气泡。浇注砼时，经常观察模板，发现有模板走动，立即停止浇注，并在砼初凝前修整完好。治理方法：砼有小蜂窝，可先用水冲洗干净，然后用12或12.5水泥砂浆修补，如果是大蜂窝，则先将松动的碎石和突出颗粒剔除，尽量形成喇叭口，外口大些，然后用清水冲洗干净湿润，再用高一级的细石砼捣实，加强养护。三、孔洞现象：砼结构内有空隙，局部没有砼。原因分析：1、在钢筋密集处或预埋件处，砼浇注不畅通，不能充满模板间隙。2、未按顺序振捣砼，产生漏振。3、砼离析，或严重跑浆。4、砼工程的施工组织不好，未按施工顺序
31、和施工工艺认真操作。5、砼中有硬块和杂物掺入，或木块等大件料具掉入砼中。6、不按规定下料，一次下料过多，下部因振捣器振动作用半径达不到，形成松散状态。预防措施：1、在钢筋密集处，可采用细石砼浇注，使砼充满模板间隙，并认真振捣密实。机械振捣有困难时，可采用人工捣固配合。2、预留孔洞处在两侧同时下料。下部往往灌注不满，振捣不实，采取在侧面开口灌注的措施，振捣密实后再封好模板，然后往上灌注。3、采用正确的振捣方法，严防漏振。a.插入式振捣器采用垂直振捣方法，即振捣棒与砼表面垂直或斜向振捣，即振捣棒与砼表面成一定角度，约4045。b.振捣器插点均匀排列，可采用行列式或交错式顺序移动，不混用，以免漏振。
32、每次移动距离不大于振捣棒作用半径的1.5倍。振捣器操作时快插慢拔。4、控制好下料。要保证砼灌注时不产生离析，砼自由倾落高度不超过2m，大于2m时要用溜槽、串筒等下料。5、防止砂、石中混有粘土块或冰块等杂物，发现砼中有杂物，及时清除干净。6、加强施工技术管理和质量检查工作。对砼孔洞的处理，要经有关单位共同研究，制定补强方案，经批准后方可处理四、露筋现象：钢筋砼结构内的钢筋露在砼表面。原因分析：1、砼浇注振捣时，钢筋垫块移位或垫块太少甚至漏放，钢筋紧贴模板。2、钢筋砼结构断面较小，钢筋过密，如遇粒径大碎石卡在钢筋上，砼水泥浆不能充满钢筋周围。3、因配合比不当砼产生离析，或模板严重漏浆。4、砼振捣时
33、，振捣棒撞击钢筋，使钢筋移位。5、砼保护层振捣不密实，或木模板湿润不够，砼表面失水过多，或拆模过早等，拆模时砼缺棱掉角。预防措施：1、灌注砼前，检查钢筋位置和保护层厚度是否准确。2、为保证砼保护层的厚度，要注意固定好垫块。一般每隔1m左右在钢筋上绑一个水泥砂浆垫块。3、钢筋较密集时，选配适当粒径的碎石。碎石最大粒径不得超过结构截面最小尺寸的1/4，同时不得大于钢筋净距的3/4。结构截面较小，钢筋较密时，可用细石砼浇注。4、为防止钢筋移位，严禁振捣棒撞击钢筋。5、砼自由顺落高度超过2m时，要用串筒或溜槽等进行下料。6、拆模时间要根据试块试验结果确定，防止过早拆模。7、操作时不得踩踏钢筋，如钢筋有踩弯或脱扣者，及时调直，补扣绑好。治理方法：将外露钢筋上的砼残渣和铁锈清理干净，用水冲洗湿润，再用12或12.5水泥砂浆抹压平整，如露筋较深，将薄弱砼剔除，冲刷干净湿润，用高一级的细石砼捣实，认真养护。