Selecting high-performance grouting materials generally considers three aspects:
1. Cohesiveness, cohesion Properties refer to the certain cohesion between the components of fresh grouting material, ensuring that no delamination or segregation occurs, so that the grouting material can maintain overall uniform and stable performance. Grouting materials with poor cohesiveness can easily cause the mud to separate from the aggregate, and honeycombs, cavities, etc. may easily appear after pouring. Excessive cohesiveness will easily lead to poor fluidity of the grouting material, which will flow to the construction location and fail to make better contact with the contact surface, affecting the pouring quality.
2. Fluidity. Fluidity refers to the ability of fresh grouting material to flow and fill the template evenly and densely under the action of its own weight or mechanical vibration. The fluidity directly affects the ease of construction and the quality of the hardened grouting material. If the grouting material is too dry and thick, it will be difficult to form and compact, and it will easily cause defects such as internal or surface holes; if the grouting material is too thin, it will It is easy for cement slurry and water to float while aggregates such as quartz sand will sink, which affects the uniformity of grouting material quality and the compactness of molding.
3. Water retention. Water retention refers to the ability of grouting materials to retain internal moisture. Grouting materials with good water retention will not cause serious bleeding during the construction process. Part of the water in the grouting material with poor water retention is easy to precipitate from the inside to the surface, leaving many capillary pores where the water seeps out, which will become the internal water permeable channel of the grouting material in the future. This problem will affect the durability and be easily cracked by freezing in winter.
Therefore, mix ratio selection can simply be regarded as the process of selecting appropriate materials and determining their relative dosage, in order to prepare as economical as possible and with certain properties - especially It is a grouting material that has the strength, durability and required consistency to meet design requirements.
Although structural design usually does not care about the specific "mix ratio selection" to express it. However, designers have five judgment criteria when selecting the mix ratio: strength, durability, water retention, cohesion, and fluidity of the grouting material. Another important thing to add is that the slump loss of the mixture must be controlled within a certain range during pouring. Since the required workability of the mixture is related to the on-site bead mixing environment, it is usually not necessary to determine the specific workability before on-site construction.
When selecting the grouting material mix ratio, the transportation method of the grouting material must also be considered, especially when the grouting material is to be pumped. Other important criteria include setting time, degree of bleeding, ease of wiping, etc., which are all interrelated. Major difficulties can arise if these criteria are not taken into account when selecting or adjusting mix proportions. When selecting grouting materials, we must start with performance. It can be said that studying the performance of grouting materials is mainly to select the appropriate mixture composition. Therefore, when selecting grouting materials, we must consider the different properties of grouting materials.
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