Support - grouting material gradation requirements Shenyang grouting material

Bearing grouting support grouting specification pedestal grouting material specification on how to find a pedestal grouting material gradation of aggregate specimen, but still unable to determine whether a particular gradation of aggregate, a related problem is the combination of coarse and fine aggregate, in order to get the required grading. What, then, is one of the characteristics of high quality grading curve? Water cement ratio, must be fully compacted bearing strength of grouting material has nothing to do with the gradation of aggregate, thus grading originally only because of workability chuzhou pedestal grouting material has important influence. However, relative to a given water cement ratio, strength of growth need to be fully dense, and have the greatest density of mixture. Should first pointed out that there is no ideal gradation curve, but a comprehensive consideration is necessary. In addition to the physical requirements, must buy consider where pedestal grouting material in shaoxing economic problems, pedestal grouting material must be used cheap materials, so can't have too much demand for aggregate. Has pointed out the main factors that control required by the aggregate gradation is: aggregate surface area, which determines the moist all the solid water required, the relative volume, accounted for the aggregate mixture of liquidity and the trend of segregation. Workability and no segregation trends are not entirely opposite: the requirements of different size of bearing material particles easily fill compaction grouting, the gap between smaller particles can enter the larger particles, but the small particles also easily by vibration wave from the space, which is easy to separate when dry. In fact, should avoid mortar ( Both the mixture of sand, cement and water) Flows freely from coarse aggregate void. Composite aggregate voids should be small enough to prevent slurry through and segregation, it is very important. Therefore, the problem of segregation and filtering are similar, but the requirements of both the opposite, for qualified support grouting material, avoid segregation when the basic requirements. With satisfactory caking and liquid mixture as well as further requirements: it must contain sufficient quantity of less than 300 um mesh material. Due to the cement particles are also included in the material, thus a rich mixture of fine content is lower than lean mixture. If in the grading of sand lacks finer particles, improve the fine/aggregate ratio could not obtain satisfactory remedy, because it may lead to medium size particles and may cause too much work hardening. So-called dry mixture stiffness is too much in the same size of the particles, and make the central gradation curve is very steep, and thus cause bearing grouting material interference between the aggregate particles. This requires enough content of fine aggregate.