The Right Tool - Chemicals
Chemistry plays a large role in concrete polishing. Although some would try to convince you that they are not needed I believe they are essential to creating a truly sustainable floor.
I read an article this week sent to me by a friend that asked the question; “ Are hardeners effective?” (http://www.concreteconstruction.net/concrete-slabs-and-floors/are-hardeners-effective_o.aspx) The author explains that he has monitored 6 projects and had concluded that, of those six, neither has benefited from the application of liquid hardeners (aka densifier). The article states that there are some outrageous claims by manufacturers - and that’s probably the only statement in the article that I’m in agreement with.
Densifiers have been in existence to treat concrete substrates for a very long time, and their benefits have been documented time and again. It’s unfortunate that some manufactures make outrageous claims about their products, oftentimes giving the entire product range a poor rating and leading to confusion and doubt by applicators.
HTC recently introduced our own line of densifiers and stain protection products in the U.S. To be honest, it’s not a new blend, it’s not some concocted “magic juice”, and it won’t solve all of your issues when polishing concrete! It is a proven formula that we have sold through our other subsidiaries that helps to increase the abrasion resistance of concrete (when applied properly - which is to rejection) and helps the diamond tooling to refine the concrete surface. When applied properly, it will also help to decrease permeability of the concrete surface. I’ve recently used HTC Densifier on two projects and found it to work very well to help reach the intended DOI (distinctness of image) and Gloss requirements for the projects. Although these projects involved “hard” concrete, the projects would not have been a success without the applications of densifier.
Most contractors confuse concrete’s compression strength with abrasion resistance, and that can be a costly mistake for a project. When concrete hydrates, it gains compression strength and abrasion resistance but at two completely different rates. Compression strength is the designed load capability of the concrete substrate. This is tested by placing small sections of the concrete substrate in a hydraulic press and gauging the PSI (pounds per square inch) upon which it breaks. Abrasion resistance isn’t checked at all for concrete substrates. Although this can be tested, there are few devices available to test for abrasion resistance in the field and they are destructive test. Therefore, most abrasion resistance claims go unchecked except for the performance of the flooring under service. This too is a poor method of measuring abrasion resistance because you have introduced a number of other variables like routine maintenance, traffic, environmental effects, etc.
When you are familiar (very familiar) with how your diamond tooling is supposed to perform under certain conditions, and you monitor your job site conditions closely, you will begin to learn what is effecting the performance of the diamond tooling vs. the concrete substrate. Most contractors don’t monitor the performance of the concrete surface during the processing and therefore don’t have a scientific basis for making adjustments. You learn to go with your gut feelings and, in most cases, that gets the results you need if you’re a veteran technician. However, a mistake in judgement still leads to loss of time and additional materials to rectify.
Learning to rely on surface profile measurements (some more reliable than Ra), DOI (distinctness of image), Gloss, Haze and Rspec values will ultimately help you take the guesswork out of the project and put more money into your pocket. How does this relate to the use of densifiers? Diamond tooling (all diamond tooling) is designed to perform a certain “function” under specific perimeters (weight, temperature and abrasion resistance). If you’re monitoring the known performance of the diamond tooling and not getting the intended results, the outlying variable is the concrete substrate. You can alter the concrete substrate using liquid hardeners to increase abrasion resistance. One manufacturer (not HTC) completed some independent testing on major brand densifiers before entering the market with their own. What they found was that the application of densifier along with the polishing process increased the abrasion resistance of the concrete surface approximately twenty six percent. Twenty percent of that increase was attributed to the chemical hardener with the remaining six percent due to the refinement of the concrete surface.
Our other two products, HTC PSP (Penetrating Stain Protection) and SP (Stain Protection) are necessary for projects that involve colored dyes or require additional protection from topical, penetrating contaminants. Both have been tested and proven to perform well under normal conditions (again, not going to make outrageous claims here that they will resist Skydrol!). My preference is the use of HTC PSP as it is a totally penetrating product that will not leave a micro film and therefore requires less maintenance. I have personally used PSP on projects and found it to be useful in creating a barrier for liquids without altering the surfaces appearances in any way. The SP will increase the gloss values slightly and requires an experienced technique to apply to my satisfaction (very, very thin coats).
HTC is known for the quality of their products and I’m sure the use of HTC chemicals will not disappoint even the seasoned veteran to our industry. If you try them and find that they don’t perform as I’ve stated, please contact me and I will gladly discuss the project conditions to help find a solution.