Ask a question about Crystal infiltration? Waterproof mechanism and detection method of Crystal infiltration?

[Shamil]

Everyone, I am a novice in waterproofing. Now I have a few questions that need to be clarified. So I'm seeking advice here:

1. What is Crystal's basic shape (or crystal form) in the Crystal infiltration activity of parent material?

2. If it is permeable non-crystalline, what are the differences between its waterproof mechanism and osmotic materials?

3. How to improve the anti-corrosion performance of cement-based waterproof materials? How to detect it?

 

[Cassie]

Regarding the mechanism of Crystal infiltration, the substances participate in the chemical reaction of cement to improve the hydration probability of cement and the activity of secondary hydration. Therefore, the crystallization of Crystal infiltration activity of parent material should be conceptualized. How can concrete be blocked by purely relying on it? It is the crystallization of the secondary hydration of cement.

The primary mechanism of waterproofing should be that hydration stones and gels block pores and microcracks.

There is a particular reason that Cement-based materials can improve corrosion resistance. When the concrete is dense, the permeability of substances such as chloride ions will be much worse, and the affinity between the mortar and the steel bar will be improved, as well as between the hydration material and the aggregate, due to the effect of the hydration gel.

 

[Luis]

If it is the mixed type, what A says is reasonable, but what about the coating type? For the coating after 3 days of substrate maintenance, it should be applied when the hydration reaction of the substrate is less, which is conducive to the penetration of crystals and improves the bonding strength. So then, the effect of waterproofing should mainly depend on the coating and the surface layer with Crystal infiltration.

As for detecting corrosion resistance, measuring electric flux should be used to detect thinner coatings, and the RCM method is more suitable for thick layers.

Also, secondary anti-seepage is very important since it is a cement-based Crystal infiltration. The secondary anti-seepage reflects the product's Crystal infiltration ability to repair gaps and cracks. Therefore, the standard should bundle the primary and secondary impermeability testing into mandatory testing.

 

[Cassie]

If it is the mixed type, what A says is reasonable, but what about the coating type? For the coating after 3 days of substrate maintenance, it should be applied when the hydration reaction of the substrate is less, which is conducive to the penetration of crystals and improves the bonding strength. So then, the effect of waterproofing should mainly depend on the coating and the surface layer with Crystal infiltration.

As for detecting corrosion resistance, measuring electric flux should be used to detect thinner coatings, and the RCM method is more suitable for thick layers.

Also, secondary anti-seepage is very important since it is a cement-based Crystal infiltration. The secondary anti-seepage reflects the product's Crystal infiltration ability to repair gaps and cracks. Therefore, the standard should bundle the primary and secondary impermeability testing into mandatory testing.

The coating also has a Crystal infiltration mechanism. So what you mentioned needs to be corrected. If it is paint and surface layer, it is waterproof mortar. The backside must have good permeability.

 

[Luis]

The coating also has a Crystal infiltration mechanism. So what you mentioned needs to be corrected. If it is paint and surface layer, it is waterproof mortar. The backside must have good permeability.

You are right. I didn’t think carefully because the tests are all formed impermeable test blocks, which basically will not crack, and there is no way to reflect the performance of Crystal infiltration, but the size of the cracks is not easy to control. However, after the primary anti-seepage is completed, the soluble substances in the concrete should be dissolved to form continuous voids in those places that have penetrated, and these voids can also reflect the effect of Crystal infiltration.

As for why the backside is used upstairs, my understanding is: first， the active substance that is beneficial to prevent recrystallization of the coating during curing dissolves in the curing water and fails to play a role in the concrete. Second, it can prevent the layer from cracking and cause the test to fail when the anti-seepage mold is installed. In addition, the backside is relatively flat.