保定市防撞墙模具厂

Quality assurance measures for construction of bridge anti-collision wall

1 模板的安装

1 template installation

用于防撞墙的模板不宜采用小块组合式钢模板，而应采用大块钢模板。这是因为模板越小， 接缝越多，外观越差，而且接缝处表面不易平整，也易出现漏浆现象。控制钢筋保护层厚度 可使用小石块来填隔钢筋，不宜采用混凝土垫块，以免在拆模后墙体表面出现一块块难看的斑痕，立模时，在防撞墙侧模的顶部与底部分别安装一根用槽钢制作的横带螺丝杆固定。然后，在两侧的槽钢上均匀地安装几根钢支撑杆，使模板的整体得到固定。

It is not suitable to use small combined steel formwork instead of large steel formwork. This is because the smaller the template, the more seams, the worse the appearance, and the joint surface is not easy to smooth, but also prone to leakage phenomenon. Controlling the thickness of the steel protective layer can use small stones to fill the steel bar, not the use of concrete pads, so as to avoid the surface of the wall after the demolition of a piece of ugly spots, when erecting the form, the top and bottom of the side mold of the anti-collision wall are fixed with a cross-strap screw made of channel steel. Then, several steel braces are evenly installed on the sides of the channel steel, so that the overall formwork is fixed.

2 混凝土质量控制

2 concrete quality control

由于防撞墙底宽上窄，其内部的钢筋布置较密，浇注混凝土施工时不利于排除气泡，所以对混凝土的和易性有较高的要求。

Because of the narrow bottom width of the anti-collision wall, the inner reinforcement arrangement is dense, and it is not conducive to eliminate air bubbles in the concrete pouring construction, so the workability of the concrete is higher.

在施工中，为了使混凝土的和易性更好，需要对集料的级配进行认真设计和调整，使其达到 最佳的级配曲线，可采用适当增加水泥用量及适当提高砂率的方法来处理，正常情况可将砂 率提高2%～3%，但砂率不能太大，含砂量过多，会使混凝土中的气泡难以上升逸出。在拌和 混凝土时，要注意拌和时间适当。拌和时间过长，会降低混凝土的和易性；而拌和时间太短 ，又不能得到匀质的混凝土，且会降低混凝土的强度。

In construction, in order to make concrete more workable, it is necessary to design and adjust aggregate gradation carefully so as to reach the best gradation curve. Appropriate increase of cement dosage and sand rate can be used to deal with it. Under normal conditions, the sand rate can be increased by 2%-3%, but the sand rate can not be too high and the sand content is too high. Many will cause the bubbles in concrete to rise and escape. When mixing concrete, pay attention to proper mixing time. Too long mixing time will reduce the workability of concrete, too short mixing time can not get uniform concrete, and will reduce the strength of concrete.

3 混凝土的浇筑与振捣

3 concrete placement and vibration

防撞墙混凝土坍落度控制在14±2cm，混凝土采用罐车运输，罐车驶至桥下后，采用龙门吊配合吊斗方式入模，混凝土到现场后先检测塌落度及含气量，符合要求后方可施工。防撞墙混凝土采用分层法进行浇注，每层浇筑厚度不得超过300mm。下料时不得在一个地方集中下料，防止形成起伏不定的界面。浇筑到护栏的倒角位置应暂时停止下灰，待该范围振捣完成后再继续浇筑。分层浇筑间隔时间应不大于混凝土的初凝时间。振捣棒应插入下层50～100㎜,振捣棒与侧模应保持50～100㎜的距离，严禁振捣棒直接接触模板。每一次振捣必须振捣至混凝土停止下沉，不再冒气泡，表面呈现平坦、泛浆时方可提出振捣棒。

The concrete slump of the anti-collision wall is controlled at 14 65507 The anti-collision wall concrete is poured by layered method, and the thickness of each layer can not exceed 300mm. When cutting, it is not allowed to concentrate in one place and prevent the formation of fluctuating interfaces. The position of the chamfering poured into the guardrail shall be temporarily suspended until the vibration is completed. www.uxingcaomuju.net.cnwww.jianchajinmoju.cnwww.jinzhouyanglao.cnwww.jinzhoubanjia.cn

www.diandongmenj.com.cnwww.gougaibanmoju.cnThe interval time of layered pouring should not be greater than the initial setting time of concrete. The vibrating rod should be inserted into the lower layer 50-100_, the distance between the vibrating rod and the side mold should be kept 50-100_, and the direct contact of the vibrating rod with the mold is strictly prohibited. The vibrating rod can be put forward only when the concrete stops sinking and no bubbles are produced and the surface is flat and flooded with slurry.

护栏顶面混凝土分三次进行收面作业。混凝土浇注后2～3小时采用木抹进行第一次收面，5～6小时用铁模进行第二次收面，混凝土初凝前完成第三次收面作业，收面时重点控制混凝土表面平整度，确保护栏顶面平整，线形顺畅。

The concrete on the top surface of the guardrail is divided into three operations. After concrete pouring 2-3 hours, wood wipe is used for the first closing, 5-6 hours with iron mold for the second closing, concrete before the completion of the third closing operation, closing the focus on the control of concrete surface smoothness, to ensure that the top of the guardrail smooth, smooth line.

4 养护与拆模

4 curing and stripping

撞墙模板拆除时间根据气温实行动态调整，目前模板拆除时间控制在混凝土浇注完成后24小时左右，模板拆除时现场设专人指挥，防止拆模过程损坏混凝土边角。

The demolition time of the formwork against the wall is dynamically adjusted according to the air temperature. At present, the demolition time of the formwork is controlled about 24 hours after the concrete pouring is completed. The demolition of the formwork is under the command of a special person on the spot to prevent the damage of the concrete corner during the demolition process.

养护：防撞墙混凝土浇注完成后，采用塑料薄膜对混凝土顶面进行覆盖湿水养护，防止气温过高混凝土表面发生裂缝，模板拆除后，及时用土工布对防撞墙混凝土进行包裹，并洒水养护，养护时间不小于7d，为确保养护质量，桥面专门设置二道自来水管用于养护供水。

Maintenance: After pouring the concrete of the anti-collision wall, the top surface of the concrete is covered with plastic film for wet water curing to prevent cracks on the surface of the concrete with excessive temperature. After demolishing the formwork, the concrete of the anti-collision wall is wrapped with geotextiles in time and maintained with sprinkler water. The curing time is not less than 7 days. In order to ensure the quality of the maintenance, the bridge is built. The surface is specially equipped with two self running water pipes to maintain water supply.

5 防撞墙施工出现质量问题及改进措施

5 quality problems and improvement measures of anti-collision wall construction

5.1防撞墙顶部圆弧部分混凝土缺边掉角的改进措施

5.1 improvement measures for concrete missing corner of the top part of the anti-collision wall

由于防撞墙顶部圆弧位置混凝土施工中不易振捣密实，模板拆除后，圆弧位置混凝土成型质量较差，混凝土光洁度不良，缺边掉角现象较多，针对这种现象，项目部采用了第二次收面过程中使用小平板振捣器二次复振的方法，有效改善了防撞墙顶部混凝土的密实度，显著提高了防撞墙顶部圆弧位置混凝土的外观质量。

Because it is not easy to vibrate and compact in the construction of concrete at the top of the anti-collision wall at the circular arc position, after the demolition of the formwork, the molding quality of the concrete at the circular arc position is poor, the smoothness of the concrete is poor, and the phenomenon of missing edges and corners is more. In view of this phenomenon, the project department adopts the method of secondary vibration with small plate vibrator in the second finishing process. The compactness of the concrete on the top of the anti-collision wall is effectively improved, and the appearance quality of the concrete at the arc position on the top of the anti-collision wall is remarkably improved.

5.2防撞墙混凝土裂缝的改进措施

5.2 improvement measures for concrete cracks in anti-collision wall

首件防撞墙施工后，防撞墙混凝土顶面出现了较多的微小裂缝现象，经过分析研究，项目部对防撞墙及波形护栏基础分三次进行收面，混凝土初凝前使用铁摸进行最后一遍压光收面处理，通过收面愈合之前混凝土表层产生的塑性裂缝，收面完成后，混凝土顶面及时覆盖一层塑料薄膜，并对混凝土顶面湿水养护，波型护栏基础混凝土收面时，因工作量较大，收面时间较长，现场在波型护栏基础混凝土顶面以上40cm高度搭设了一道土工布，以减小波型护栏基础混凝土表面温度及风速，减小顶面裂缝现象。通过工艺改进，防撞墙顶面裂缝现象显著减少，混凝土表观质量得到有效控制。

After the construction of the first anti-collision wall, there are many small cracks on the top of the concrete of the anti-collision wall. Through analysis and research, the project department has finished the anti-collision wall and the wavy fence foundation three times. The concrete is treated with the iron touch for the last pressing finish before the initial setting, and the plasticity produced in the concrete surface before the surface is healed. When the surface of concrete is closed, a layer of plastic film is covered on the top of the concrete in time, and the wet water curing of the top of the concrete is carried out. When the concrete of the wave-shaped guardrail foundation is closed, a geotextile is laid at the height of 40 cm above the top of the concrete of the wave-shaped guardrail foundation in order to reduce the wave-shaped protection. The surface temperature and wind speed of the concrete are reduced to reduce the cracks on the top surface. The cracks on the top of the anti-collision wall have been significantly reduced and the apparent quality of concrete has been effectively controlled by technological improvement.