1水泥一般选用普通硅酸盐水泥或硅酸盐水泥,初凝时间宜不早于1.5h,宜选用标号在325以上的水泥。所选的水泥品种应通过初凝时间和抗压强度试验。要注意水泥的用量要达到规范规定的标准。
1 Portland cement or Portland cement are generally used for cement. The initial setting time should not be earlier than 1.5 h, and the cement labeled 325 or more should be selected. The selected cement varieties should pass the initial setting time and compressive strength test. Attention should be paid to the amount of cement to meet the standard stipulated in the code.
2.粗骨料宜选用坚硬的卵砾石和碎石。骨料最大粒径不应大于导管直径的1/6~1/8 和钢筋最小净距的1/4同时粒径在40mm 以内。粗骨料的级配应保证混凝土具有良好的和易性。细骨料宜采用级配良好的中、粗砂。混凝土的含砂率一般为45%~50%,水灰比宜采用0.5~0.6。
2. Hard gravel and gravel should be selected for coarse aggregate. The maximum particle size of aggregate should not be greater than 1/6-1/8 of the diameter of conduit and 1/4 of the minimum net distance of reinforcing bar, and the particle size should be less than 40 mm at the same time. The gradation of coarse aggregate should ensure that concrete has good workability. Fine aggregate should adopt medium and coarse sand with good gradation. The sand content of concrete is generally 45%-50%, and the water cement ratio should be 0.5-0.6.
3.为提高和易性,混凝土中宜掺入外加剂,掺入外加剂前,必须经过实验,以确定外加剂的使用种类、掺入量和掺入程序。
3. In order to improve the workability, admixtures should be added into concrete. Before admixtures are added, experiments must be carried out to determine the types of admixtures used, the amount of admixtures and the procedure of admixtures.
4.混凝土的配合比必须与导管灌注水下混凝土相适应。合适的配合比应使混凝土具有足够的可塑性和粘聚性,易于在导管中流动而不易离析。而且一般来说,当水下混凝土的强度高时,其耐久性也好。因而要从水泥标号的选择、水泥及水的用量比例、骨料的种类和性质及掺用外加剂等几个方面的考虑来保证混凝土质量。混凝土搅拌时间要适宜,要搅拌均匀,如混凝土搅拌和输送过程中出现不均匀或离析泌水现象,流动性差时,就不能使用。
4. The mix ratio of concrete must be compatible with the underwater concrete filled with conduits. Suitable mix ratio should make concrete have enough plasticity and cohesion, easy to flow in conduit and not easy to segregate. Generally speaking, when the strength of underwater concrete is high, its www.hanbaiyushidiao.cnwww.shaiban.net.cnwww.shidiaodaxiang.cnwww.xiaoxieqi.com.cn
www.banjiacz.cnwww.datongbanjia.cndurability is also good. Therefore, the quality of concrete should be guaranteed by the selection of cement label, the proportion of cement and water, the type and properties of aggregate and the addition of admixtures. Concrete mixing time should be appropriate, to mix evenly, such as concrete mixing and conveying in the process of non-uniform or segregation bleeding phenomenon, poor fluidity, can not be used.
浇筑过程中需要注意的事项:在浇筑过程中,混凝土拌至成功后,应在1.5小时之内尽量浇筑完成,避免银停留时间过长而导致的混凝土直接凝固的情形发生,加快生产周期效率。
Pouring process should pay attention to matters: in the pouring process, after the concrete mixing is successful, it should be poured as far as possible within 1.5 hours to avoid the direct solidification of concrete caused by the long silver residence time, and to speed up the production cycle efficiency.