What are the main factors affecting the shrinkage compensation effect of grouting materials?
Feb 11, 2023
What are the main factors affecting the shrinkage compensation effect of grouting materials?
Grouting materials need to be carefully maintained in order to make their performance better. So what are the main factors that affect the shrinkage compensation effect of grouting materials? Mainly: types of expansion agent, types of cementitious materials, dosage of expansion agent, design factors, construction conditions, maintenance conditions, etc. Let's break it down.
1. Influence of expansion agent species
Different types of expansion agents have different mechanisms for compensating shrinkage. The expansion agent with ettringite as the expansion source may also have great differences in performance due to different raw materials.
2. The influence of the amount of expansion agent
The amount of expansion agent should be appropriate, and the amount of expansion agent should not be less than the lower amount that meets the performance requirements of the grouting material, nor should it be higher than the higher control amount. If the amount of expansion agent is too small, the purpose of compensating shrinkage cannot be achieved; if the amount of expansion agent is too large, the expansion agent may crack in the grouting material, and the manufacturing cost of the grouting material will be increased.
3. The influence of the type of cementitious material
Different types of cementitious materials have different effects of expansion agents. The effect of using expansion agent in pure clinker Portland cement is better than that of cement containing mixed materials; when the content of aluminate or SO3 in the cementitious material is high, the effect of expansion agent is better; in the mixed material, Metakaolin has good volume stabilization effect.
4. Influence of construction conditions
Even with a good quality expansive grout, the grout structure can crack or seep if not properly applied. As far as the leakage of the grouting material project is concerned, the incomplete vibration can lead to the leakage of the grouting material; improper construction of waterproof nodes will also cause leakage.
5. The influence of maintenance conditions
Careful maintenance is an important condition to ensure the best performance of shrinkage-compensating grouting materials. Whether it is a calcium sulfoaluminate expansion agent or a calcium oxide expansion agent, water is needed when the volume expansion occurs in the cement grouting material, and the mixing water is not enough to make it produce sufficient volume expansion. It is necessary to strengthen early wet curing.
