On a summer’s morn, the lotus leaves unfurl and sway with a gentle grace, their layered hues resembling a palette of vibrant colors. Upon these verdant canvases, dewdrops descend with a delicate touch, each one a tiny herald that stirs the world from its slumber.
If you’re poetic and emotional, then you may recite the old poetry like:
In English, it depicts the first appearance of the Udumbara with rounded leaves, like scattered bright pearls moving on a green plate.
And if you’re rational and more likely to be a Science Major, you will say: That’s the Lotus Effect, which means a natural phenomenon where lotus leaves repel water and dirt. This happens because the leaf surface has tiny bumps and a waxy coating, causing water to form droplets that roll off, taking dirt with them. This self-cleaning ability keeps the lotus plant clean and dry.
We apply the lotus leaf effect to Construction additives, using ingredients such as silane, siloxane, and fluorocarbons to reduce the surface energy of the material and make water molecules form a larger contact angle, thereby achieving waterproof and self-cleaning effects. We can simply call it principle Immersion, meanwhile, there are still other two principles Shielding and Clogging, which each has its own advantages and disadvantages. can be used alone or in combination with three principles.
That kind of Hydrophobic agent, or called water repellent agent, nowadays is widely used in concrete, masonry, gypsum boards, coatings, and other fields to improve the waterproof properties and durability of materials.
In this article, we only talk about water repellent applications in construction areas. Compared to the renowned ones like Master Protect H 700 from BASF and Sika®-1, Cemotech’s water repellent: Aquago® WP200 and Aquago® WP200H could be counter types and will be used as examples in this article.
When we do the Brush Test of Lotus Effect with Aquago WP200H
(the Lotus Effect with different dosages)
The Lotus effect after 1 hour
From the test, it is obvious that the dosage of 0.2% has the best Lotus effect
Also, we can do the brush test with a 1% dosage of water repellent agent:
The substrate of column A adds no water repellent agent, and the one of Column B with one competitor’s, Column C adds Aquago WP200H, we took 4 different times to record the change, which shows a significant difference in anti-seepage effect.
However, it is not always the more, the better.
Before adding water repellent agent, we should know some facts:
The effect of water repellent on Setting Time, Fluidity, Flexural Strength, and Compressive Strength
From the tables, we could know that we should adjust the dosage according to specific requirements. It is not just about increasing the dosage to improve the waterproofing effect. Changes in strength caused by excessive dosage also need to be considered.
How to test the water absorption property？
Water absorption test： The test method refers to the European standard EN 1062-3
Calculation formula：—— Q=W×h0.5
In the formula：
Q——Water absorption capacity
W——Water absorption coefficient
h——Water absorption time
EN 1062-3 divides water absorption into three categories, with the third category having the best impermeability effect.
1) High water absorption coefficient: > 0.5
2) Medium water absorption coefficient: 0.1 – 0.5
3) Low water absorption coefficient: < 0.1
Conclusion
For applications where waterproofing is required, using a hydrophobic agent is a wise choice. The proportion of waterproofing agents in the formula needs to be adjusted according to specific parameter requirements. Cemotech’s Aguago series of hydrophobic agents can effectively reduce the water absorption and water seepage of the substrate, and greatly improve the waterproof performance.
