High Performance Concrete Admixture

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Author Message J. Peter Jordan Senior Member Username: jpjordan Post Number: 545 Registered: 05-2004 Posted on Monday, March 25, 2013 - 11:00 am:    Has anyone had any experience with Barrier One High Performance Concrete Admixture (see http://www.barrierone.com/). This company claims to have developed a product that will eliminate concerns about moisture in concrete slabs interferring with flooring installations. They offer a pretty good warranty, but I really don't understand how it would work. ken hercenberg Senior Member Username: khercenberg Post Number: 475 Registered: 12-2006 Posted on Monday, March 25, 2013 - 11:15 am:    Please note that I am only speaking my personal opinion and that this does not reflect in any way an opinion from my company. Having said that, I would strongly suggest staying away from this sort of product. I'll take a spray-and-pray over this any day, and I'm not a big spray-and-pray fan. Most other chemical companies who make silicate products won't touch this method of application. They understand the chemistry and physics involved much better than I do (my major in college was Physical Sciences) and they are adamant that it does not work. I believe them. Lisa Goodwin Robbins, RA, CCS, LEED ap Senior Member Username: lgoodrob Post Number: 213 Registered: 08-2004 Posted on Monday, March 25, 2013 - 11:31 am:    Our company opinion is that there is no scientific evidence supporting their claims. - Richard L Matteo, AIA, CSI, CCS Senior Member Username: rlmat Post Number: 571 Registered: 10-2003 Posted on Monday, March 25, 2013 - 11:46 am:    First - I have to state, as does Ken, that this is my personal opinion and not necessarily that of my employer. I too do not like the "spray-and-pray" products and tend to stay away from them in favor of more "bullet-proof" systems. spiper (Unregistered Guest) Unregistered guest Posted on Monday, March 25, 2013 - 12:28 pm:    Our office also believes that this product looks "to good to be true" so we assume it is not. The best method for moisture issues in new slabs will always be time. In addition we have been revising our specs to include more wet-curing where possible as well as working to avoid the hard steel trowel finish that so many installations have. The steel trowel looks nice but tends to slow the drying process. We also have been eliminating "cure and seal" because the seal part does just that and then the slab is less likely to dry out in time for flooring installation. Time is money and as such waiting is not always an option but it should be considered if at all possible. There is also a rapidly expanding library of superior adhesives that will allow a much higher RH and still warranty the system. I do miss the "good old days" when you could apply cut-back adhesive to the back of Rhinoceros and the tiles would have stuck. Eric D Lussier (Unregistered Guest) Unregistered guest Posted on Tuesday, March 26, 2013 - 10:02 pm:    Peter and All, I just sat through a presentation with Barrier One at the CSI Vermont meeting last Thursday, 3/21. As a flooring distributor and installer, concrete MVER is a huge issue that we face on almost a daily basis. I wrote a blog post about it late last year here: http://ericdlussier.wordpress.com/2012/12/04/know-your-floor-and-know-your-mver/ I will say that the presentation was impressive. We have a former employee who works for a concrete testing company and they have been hired during concrete placement by Barrier One. While concrete moisture is always there and is always an issue, our biggest headache is the timeframe that flooring has to be installed vs. the time that a space is truly deemed ready. I've seen wood flooring installed while front doors and windows less than 100 feet away are still not installed. We all could use acclimated spaces earlier in the project. Tony Wolf, AIA, CCS, LEED-AP Senior Member Username: tony_wolf Post Number: 50 Registered: 11-2007 Posted on Wednesday, March 27, 2013 - 12:06 am:    It does sound too good to be true, but that in itself does not mean it doesn't work. And I certainly can't speak to the chemistry. It's possible the manufacturer is a bold face liar, and/or just dead wrong. But the manufacturer has significant amount of the product installed, and is completely open with its project references. The question in my mind is this: Are there any reports of it failing? Considering the potential upside of this product, collecting such real-world experience [good and bad] seems worthwhile, and is what I think Mr. Jordan hoped to accomplish when starting this topic. I would sure like to hear it. J. Peter Jordan Senior Member Username: jpjordan Post Number: 549 Registered: 05-2004 Posted on Wednesday, March 27, 2013 - 10:24 am:    There are bold architects and there are old architects; there are very, very few old bold architects. Spec writers tend to get less bold younger. Anne Whitacre, FCSI CCS Senior Member Username: awhitacre Post Number: 1325 Registered: 07-2002 Posted on Wednesday, March 27, 2013 - 02:29 pm:    There are a few concrete additive systems out there now that promise more consistent finishing and better consolidation. On one of my previous projects, we used iCrete, and the contractor was able to reduce the slab thickness by 2 inches and consistently finish 2 floors every three weeks. For an 80 story building it was substantial savings in time and space. Their system involved continuous measurement of the moisture level of the concrete as it was pumped, and then an additive was put in either accelerating the mixture or retarding it, depending on the characteristics of the mix that day (relative humidity, absorption of the cement, etc). I think the industry is going toward optimized mixes, but it does take some skill to interpret the result and adjust the mix. John Bunzick, CCS, CCCA, LEED AP Senior Member Username: bunzick Post Number: 1491 Registered: 03-2002 Posted on Wednesday, March 27, 2013 - 03:11 pm:    Reducing slab thickness affects the fire-resistance rating (ASTM E119) of the slab. For many of our projects, that was the determining factor in deciding slab thickness. Check this before you use this approach. Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 547 Registered: 10-2007 Posted on Wednesday, March 27, 2013 - 05:35 pm:    What was it about the admixture that allowed the slab thickness to be reduced?? Anne Whitacre, FCSI CCS Senior Member Username: awhitacre Post Number: 1326 Registered: 07-2002 Posted on Thursday, March 28, 2013 - 12:22 pm:    "what was it ... that allowed slab mixture to be reduced". My understanding is that it was easier consolidation, and higher strengths. We're not talking 6 inch slabs to 4 inch slabs -- it was more like 13" slabs reduced to 11" slabs. it was a Type 1 building, and a concrete frame, not a steel frame. The project was built in New York City, and the contractor had experience with the optimized mixes and the measuring equipment. Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 548 Registered: 10-2007 Posted on Thursday, March 28, 2013 - 02:34 pm:    Firsts realize that NYC is in its own universe when it comes to construction practices. When I checked out iCrete it appears to be a software package that helps the concrete supplier optimize the design of the concrete mix. iCrete is not an admixture although the mixes produced probably use admixtures. They could have produced the higher concrete strengths without the software. There are admixtures that help reduce problems with congestion that are used all the time. Reducing the slab thickness will increase congestion. Reduction in slab thickness was likely the result of the Contractor and engineer doing cost studies considering the tradeoffs between added cement and reinforcement versus the cost of the concrete reduced. Richard L Matteo, AIA, CSI, CCS Senior Member Username: rlmat Post Number: 572 Registered: 10-2003 Posted on Thursday, March 28, 2013 - 02:46 pm:    Gee, I thought California was the only one in its own universe! As an Architect and not a Structural Engineer, I'm still leery about additives/admixtures to concrete, especially when it comes to MVE. As I mentioned, I like the applied products that can be applied over both new and existing slabs (which by the way can still have moisture in them). Any one remember the old "ChemComp" product that was supposed to eliminate shrinkage cracking in concrete slabs? To my recollection, it never worked. Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 550 Registered: 10-2007 Posted on Thursday, March 28, 2013 - 10:54 pm:    Admixtures can reduce the amount of water in the mix and reduce the permiability of the concrete. Some admixtures appear to be able to trap the moisture in the concrete and prevent it from migrating to the surface. Some admixtures can also help small cracks to heal. Will this solve your moisture problem? I do not know in part because it is not clear what the problem really is. Tests have shown that the permiability of concrete does not account for enough moisture to cause the moisture tests to fail. This suggests that the moisture is comming from another source. It has been suggested that the surface ph of the concrete plays a role. In my experience there are a lot of individuals who claim "the solution". Most of these experts must be wrong. What I do not see is a lot of science. In this context as a structural engineer I attempt to keep the water content low and then try to accomodate the architects strategy. ken hercenberg Senior Member Username: khercenberg Post Number: 486 Registered: 12-2006 Posted on Friday, March 29, 2013 - 10:53 am:    Mark, I concur with you. The less water in the concrete, and the better job the Contractor does at keeping the concrete dry once reasonable curing has been completed, the better. I learned a lot about this from Bob and Craig Higgins at Sinak in San Diego. They were among the first developers of 'spray and pray' systems and quickly learned that what worked logically didn't necessarily solve the problem. They warn against the snake oil people who use silicates as admixtures. A couple essential problems with the spray-and-pray systems are that if either the water (whatever form) or high pH layers are too close to the surface, the silicates react too soon and can't penetrate into the concrete where they do the most good. Different silicates provide different levels of defense, so sodium silicates (like Ashford Formula) help densify the concrete which, when it is crack-free, is inherently waterproof but is still vapor permeable. Other salts, like potassium silicates, have a smaller molecular structure and should help block water vapor in theory. Unfortunately, if high water vapor migration is present, the silicate reacts too quickly to offer any benefit. If there is no problem, it works fine (sorry, being cynical again). One of the biggest problems I've heard about using Silicates as admixtures is that they can create unworkable concrete. Concrete applicators have told me horror stories about their inability to float the concrete after adding these products. The discussions that were posted a year of so ago about how to deal with water vapor mitigation offered a lot of very good, real-world suggestions. I'll put my faith in those practices before trusting something that everyone I trust tells me to stay away from. I love trying new products, but change for the sake of change is a sign of ignorance in my book. Hope that helps a little. This is obviously a very simplified explanation and I've probably screwed up parts of it. Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 551 Registered: 10-2007 Posted on Friday, March 29, 2013 - 11:50 am:    Ken I do not disagree that admixtures can influence the ability to finish concrete but my impression is that the horror stories are often the result of the finishers not realizing the need to change their practices. There may be limitations on the use of the product but in many cases they can be mitigated. This is a classic problem when we specify. We cannot address all of the ways that something can be screwed up thus we are dependent on the contractor's active participation. What we have specified may be perfectly doable but if a contractor is not invested in making it work it is easy to blame the problem on the product of the specifier. My guess is that if we did nothing, in most cases there would be no moisture problem. Adding admixtures to reduce permeability and trap the water in the concrete would solve many of the additional problems. Paying attention to heating the space and providing humidity control would solve most of the other problems. Thus to the extent that these surface treatments work they are in many cases probably getting credit for solving the problem when there is no problem. But it is not in the manufacturer's interests to identify when we really need to do something. My guess is that the flooring manufacturers have used this focus on moisture flow from the slab to focus the problem away from themselves. spiper (Unregistered Guest) Unregistered guest Posted on Friday, March 29, 2013 - 12:27 pm:    Mark I would add one thing to the discussion about moisture flow in relation to the flooring manufacturers. The problem IMO has become an issue for flooring manufacturers and installers not due to increased moisuter flow but due to changes in adhesives. The elimination of high VOC and solvent based adhesives has left flooring isntallations more susceptible to moisture issues than they were in the past and this has created an entire "cottage industry" designed to counter this issue. The easiest solution would be to go back to cut-back adhesives but for a number of reasons (most of them very good reasons) this is not an option. Making the adhesives better for the planet (and all of us on it) has had an adverse affect on the flooring industry. The new "better" glues just don't stick like the old stuff. I don't think the flooring manufacturers are trying to "focus the problem away from themselves" but rather trying to work with the hand they have been dealt. I also believe that henry adhesives and others are well on their way to developing better adhesives that will withstand higher RH levels and in another decade this whole debate may be a distant memory. In the end I believe the "magic pill" will come from the adhesive manufacturers and not admixtures or moisture mitigation applications. Still we live in the present so we have to deal with it now and everyone is looking for quicker, easier and cheaper alternative to protect against flooring failures. Anne Whitacre, FCSI CCS Senior Member Username: awhitacre Post Number: 1329 Registered: 07-2002 Posted on Friday, March 29, 2013 - 01:00 pm:    spiper: there are three things that have changed that influence the flooring issues. 1) we don't typically use as lean a mix as when I started working -- we use higher water content and somewhat less cement content in the concrete mix. 2) as you noted, the adhesives are water soluble, rather than solvent based. 3) and most flooring is less permeable than it used to be. VAT (A for Asbestos) allowed small amounts of water to escape through the asbestos fibers. Carpet with jute back and hair pads allowed water to escape through those fibers. Even ceramic tile with 1/4" joints every 8 inches allowed far more water evaportation than the 36" x 36" tiles with 1/4 joints we use today. Flooring moisture problems are a confluence of all three problems. These days, we can add less water to the mix, and we could go back to solvent based adhesives. VAT isn't coming back, and only the "greenest" clients I've got would be willing to consider a jute backed carpet. (and I have not installed a hair pad in eons.) The problem isn't the moisture in the concrete, the problem is what happens when it condenses in conjunction with a latex based adhesive in a condition where no moisture can escape. spiper (Unregistered Guest) Unregistered guest Posted on Friday, March 29, 2013 - 03:16 pm:    Anne: I agree that all three items influence the situation but I would still contend that item #2 is far and away the primary reason this is an issue. 1)old slabs on grade(presumably leaner & with higer cement content) are failing in reapplications. It is not just new slabs where this has become on issue. (Old slabs probably fail due to poor vapor barriers and high moisture content in the soil and not the original mix) 2)Cut-back adhesive was tested to be successful for levels up to 25 lbs. This allowed a great deal of flexibility in terms of perm rate, vapor barrier, mix design, size or type of material. 3)I am not sure VAT was more permeable than VCT but either way the topcoat of wax creates a form of a vapor barrier anyway. I have been told that old waxes were actually less permeable than new ones so this would actually make old floors more susceptible and not less. (I may be wrong about this one but that is what I have been told.) IF this is true why don't old floors fail at a higher rate? IMO because of the solvent based, dead dinosaur goo, cut-back adhesive. In the end I don't disagree with you but still IMO the adhesives are the real problem and they will become the solution at some point as well. Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 552 Registered: 10-2007 Posted on Friday, March 29, 2013 - 03:47 pm:    In my experience we currently use lower water cementitious material ratios largely in response to the concern regarding moisture in slabs. The use of less water has been facilitated by the increased use of water reducing admixtures which make it feasible to place concrete with less water. I appreciate that the formulations of adhesive have changed but I still contend that the flooring manufacturers have done a good job of creating the perception that it is a concrete problem. By establishing criteria that in many cases is hard to achieve the flooring manufacturers positioned themselves to deny liability in many cases. spiper (Unregistered Guest) Unregistered guest Posted on Friday, March 29, 2013 - 05:18 pm:    What does everyone believe is a reasonable set of criteria for a slab (new or old) before flooring installation? RH 70%? 80%? 90%? CALC 3 lb? 5lb? 7lb? It may be that in some parts of the country the criteria are much more stringent so maybe this is a more difficult problem to address depending upon where you are? i would be curious to know what the differences might be based upon where you are and who you work with. Lynn Javoroski FCSI CCS LEEDŽ AP SCIP Affiliate Senior Member Username: lynn_javoroski Post Number: 1623 Registered: 07-2002 Posted on Friday, March 29, 2013 - 05:42 pm:    It depends on the flooring manufacturer's criteria. Generally speaking, RH of 70-75%, and 3 lb. But some floorings tolerate more (and a few less). John Bunzick, CCS, CCCA, LEED AP Senior Member Username: bunzick Post Number: 1492 Registered: 03-2002 Posted on Sunday, March 31, 2013 - 04:15 pm:    It has also been shown that pH is a significant component. Concrete is very alkali, which doesn't manifest as a problem unless it is wet. Hence moisture concern for alkalinity, which affects curing of adhesive. Also, the rate of moisture transmission is important. Slower rates are not presenting the issues that higher rates do, so some of these products work simply by slowing moisture transmission down. spiper (Unregistered Guest) Unregistered guest Posted on Monday, April 01, 2013 - 09:33 am:    I asked the question about levels based upon Mark's comment about establishing hard to achieve criteria. I would agree that asking a new slab to reach 75% and/or 3lbs. (as well as appropriate pH) is difficult to achieve without a great deal of time. Or a great deal of additional responsibilty on the batch plant and the concrete sub. On a fast track project we do not attempt to specific new slabs that will reach this level and instead utilize a upgraded adhesive that will withstand higher levels. We beleive this approach (along with some minor changes to conrete curing and finishing) allows us to leave the responsibility in the hands of the flooring contractor. Admixtures designed to do things that they may or may not be capable of doing leaves the door open for finger-pointing in the future if there is a failure. If two subs get into a battle over whose problem it is the only ones happy are the lawyers and many times the culprit (in the eyes of the owner) is the Architect. There are some flooring installations that still do not have options for higher levels but for the most part we have been able to include an optional adhesive to accommodate slab moisture transmission issues (typically with an alternate add or deduct depending on the situation). We work very hard to make reasonable demands on the concrete sub but we don't try to make them achieve mircles of science. Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 556 Registered: 10-2007 Posted on Monday, April 01, 2013 - 12:59 pm:    Spider You reinforce my contention that much of what is done in the name of moisture mitigation is a result of a desire to protect us from lawyers and is not necessarily based on good science. ken hercenberg Senior Member Username: khercenberg Post Number: 489 Registered: 12-2006 Posted on Monday, April 01, 2013 - 01:08 pm:    Agreed. Most concrete I've seen over the past few years, especially if it contained (Heaven forbid) lightweight aggregates, has been hard-pressed to get below 90% RH; 95+% RH has been the norm. Almost no one even bothers looking at the pounds of water any more since heating the space will drive the moisture down, give you time to pass the test, and then allow the moisture to rise once again and blow out your flooring. RH testing is another fiasco. Testing equipment and methods are not uniform. Who do you have doing the testing? The Owner? The flooring Installer? Will the flooring Installer accept testing by an Owner-hired agency? Is the Owner stupid enough to allow testing by the flooring Installer who has a vested interest in not having the concrete pass? What's in your spec? Steven Bruneel, AIA, CSI-CDT, LEED-AP, EDAC Senior Member Username: redseca2 Post Number: 393 Registered: 12-2006 Posted on Monday, April 01, 2013 - 02:13 pm:    To add insult to potential injury, about 10 years ago we were at the slab moisture testing point on a very large healthcare project. The results were coming in at the 5 pound point, and the specified sheet flooring required 3 pounds or less. The Owner asked us to consider alternates that would warrant at the 5 pound point. This was a big amount of sheet flooring on the table, delete the ceramic tile, epoxy terrazzo, carpet and specialty floors from the gross square feet, it still was well above 100,000 SF. When the manufacturer of the originally specified product line got wind that a change to something else might be coming, they issued a one project warranty for their product at 5 pounds, contrary to reams of their published product data. The designers and the Owner thought that this was really cool and a great solution, but I have tried to never use that manufacturer again. Between the bi-weekly calls from the spray and pray vendors and manufacturers that are willing edit their products data to suit the project (sale) you just have to double down harder. Susan McClendon New member Username: susanmcclendon Post Number: 1 Registered: 04-2013 Posted on Monday, April 01, 2013 - 03:16 pm:    This is so timely it's spooky. While looking into this sort of product, I found something a bit different: Aridus Rapid Drying Concrete by U.S. Concrete and its licensees, www.us-concrete.com/aridus. Does anyone have experience with this product? Susan McClendon Junior Member Username: susanmcclendon Post Number: 2 Registered: 04-2013 Posted on Monday, April 01, 2013 - 03:25 pm:    Discussion of Aridus: http://discus.4specs.com/discus/messages/24/6497.html Anne Whitacre, FCSI CCS Senior Member Username: awhitacre Post Number: 1330 Registered: 07-2002 Posted on Tuesday, April 02, 2013 - 05:06 pm:    The water based adhesives have all sorts of their own issues -- not only moisture in concrete, but serving as mold food -- which cutback or solvent based adhesives never did. The moisture/mold issue in construction seems like whack-a-mole to me: you change one thing to get rid of VOCs, and some other problem pops up. You fix that, and we get a whole other batch of new issues that no one was concerned with before the first issue. as for the testing, Ken, I typically ask for an independent agency to do it as part of the other testing. spiper (Unregistered Guest) Unregistered guest Posted on Monday, April 01, 2013 - 03:18 pm:    Ken brings up a difficult question. Our office still makes the flooring installer do the RH testing so he owns everything about the install. We also make sure the equipment and methods are reviewed and approved. Not a perfect solution but the best we have come up with. As for RH levels we (typically) do not have unreasonably fast tracked projects so getting under 90% is usually not a problem. Once to that point there is often an option that does not include an overly expensive MV midigation system. As an example, I just speced a Taraflex sports floor that is rated at 80% & 5lb. We think we can meet these levels based upon the schedule but we have an alternate add to go to a Sport M plus DryTex material with the Gerpur adhesive and the limits become 98% & 15lb. Total upcharge for the sq. ft. we are looking at; about $2,000.00. An Ardex MC or Koester VAP 2000 would cost closer to $11 - $12,000.00. The adhesives are getting there but there are still some big headaches as well (rubber tile appears to be very unforgiving.) G. Wade Bevier, FCSI, CCS, LEED-AP BD+C, SCIPa, USGBC Senior Member Username: wbevier Post Number: 43 Registered: 07-2004 Posted on Wednesday, April 10, 2013 - 01:26 pm:    So, in this discussion we have concluded that concrete is very critical and the performance is determined by the control of the moisture in the slab during the curing process and when the hydration has achieved a level where the intended finish can be applied. There are issues with the various adhesive options and how they perform. There are expressions of personal and in-house decisions/conclusions on how these conditions will be specified (or not specified) But what I am not seeing is any direct discussion regarding Peter's initial inquiry regarding this specific Barrier One Admix product. I know it is getting installed on a regular basis and in increasing frequency so, having some in the field actual experience with the product would now be great information to add to this topic. ken hercenberg Senior Member Username: khercenberg Post Number: 496 Registered: 12-2006 Posted on Wednesday, April 10, 2013 - 01:52 pm:    I know of at least one failure with a project while at a previous employer. I'm not comfortable talking about it since it's still in litigation and, even though I'm not involved, I don't think it would be right. I have not heard of successes from people I've met with first-hand experiences. I have met a few people at mitigation seminars, apparently either not on this forum or not willing to raise their hands, who have used it and will not willingly use it again. Sorry I can't provide more than that. I will ask around. Anne Whitacre, FCSI CCS Senior Member Username: awhitacre Post Number: 1336 Registered: 07-2002 Posted on Wednesday, April 10, 2013 - 02:28 pm:    Wade: I think it varies by region of the country. I seldom see the need for moisture mitigation in concrete out here on the west coast, unless we're trying to do something that we know will be a problem: put down a 12" slab and carpet it 3 months later. In addition, it has become very fashionable for projects to have polished concrete floors, so trapped moisture in the floors isn't an issue. The folks I've met who have used various products for moisture control 1) are directed to do so by the owner -- for whatever reason; 2) the contractor hasn't managed the schedule properly and needs the additional help or 3) are so concerned that they use a product "just in case". I haven't heard of any failures with Barrier One or other products, but I've had a lot of conversations with people who wondered if they wasted money. I would also say that I've never had a structural engineer recommend the use of such an admixture, and they would be specifying the structural slab concrete. spiper (Unregistered Guest) Unregistered guest Posted on Wednesday, April 10, 2013 - 03:01 pm:    I have attached a link to a statement from the CTL Group with regards to admixtures. The statement makes it clear that individual products would have to be researched on an individual basis. However in general as far as I can tell from the document the scientists at CTL do not see much benefit to using admixtures. The word of Howard Kanare is all the science I need to convince me that admixtures are little more than wishful thinking in most (if not all) instances. http://www.jdtechnical.com/Documents/CTL_Comments_on_silicates.pdf G. Wade Bevier, FCSI, CCS, LEED-AP BD+C, SCIPa, USGBC Senior Member Username: wbevier Post Number: 44 Registered: 07-2004 Posted on Thursday, April 11, 2013 - 09:28 am:    I have the 2010 CTL report and a letter from an ACI consultant. I have been tracking (note "tracking" not using or specifying) this product for over 10 years and still have mixed information which, to me, just perks my curiousity. I am not an advocate, one way of the other, but find it interesting that this topic continues to be a critical issue in the industry and yet there is an on going discussion with very few conclusions; or solutions. So far, it remains that it is prudent to specify a robust vapor barrier (10-15 mil, class A) in ALL on-grade instances and to be specific with the water to cement ration. Specify with caution the "arbitrary" addition of admixes, reactive aggregates, or assorted pozzolans. Use either, or both, of the two standard moisture tests and get the flooring finish provider/installer to approve the results before application. BTW - I have seen push back from the installers regarding this approval process and they are also frustrated in having the determination of the slab being adequately cured to be thier responsibility when they have little or no control over any of the factors involved with the chemistry or installation of the slab (or the Contractors construction schedule). And then, when it is all said and done, have a "back up" moisture controling remediation solution in the works, should it be needed. ken hercenberg Senior Member Username: khercenberg Post Number: 497 Registered: 12-2006 Posted on Thursday, April 11, 2013 - 10:47 am:    Wade, precisely the reason why I have testing by the Owner's testing agency and responsibility for ensuring that substrate preparation is the General Contractor's responsibility. I don't believe it's right to hold the flooring Installers responsible for something they have no control over. They just need to know that they are responsible for refusing to apply the flooring over an inadequate substrate. It is one of the reasons I include the flooring Installers in the concrete Pre-Installation Conference. Same is true for polished concrete systems since I don't want a concrete sub screwing up the curing and finishing of the concrete before the concrete polishing sub ever walks onto the site. As to silicate admixtures and 'spray-and-pray' systems, I'd say that the CTL report is enough for anyone to hang their hat on. I've seen lesser reports but the CTL is the most coherent and comprehensive response I've seen to date. Tony Wolf, AIA, CCS, LEED-AP Senior Member Username: tony_wolf Post Number: 53 Registered: 11-2007 Posted on Thursday, April 11, 2013 - 10:55 am:    Has anyone specified the testing and everything correctly, and the contractors followed requirements, and yet still had a failure? ken hercenberg Senior Member Username: khercenberg Post Number: 498 Registered: 12-2006 Posted on Thursday, April 11, 2013 - 11:24 am:    I've had projects where Owners have accepted 'VE' credits to change specified curing systems despite our recommendation to reject the change. Next thing we know we're receiving frantic phone calls because the concrete's not ready to receive flooring. Most of the pushback I've seen has been from contractors who refuse to acknowledge the need to protect the concrete from getting wet during construction. Then we get into the battle over who is responsible for the mitigation system. Some Owners bow to the 'delay' extortion, some don't. We try to make it clear that protection of the concrete is means and methods. I've been on job sites where Contractors are hosing down or power washing closed-in decks to clean them. I've reminded them that the 'drying clock' restarts every time the deck gets wet and document it in my notes. Usually happens after the deck has already been saturated by fireproofing subs or gyp board mud people who didn't bother to put down tarps or protection. There's just no talking with some people. spiper (Unregistered Guest) Unregistered guest Posted on Thursday, April 11, 2013 - 12:18 pm:    We had a failure several years ago on an existing floor slab that we attempted to put a new rubber tile floor on. At the time CaCl testing was the standard and the slab passed easily. However the ground water level increased months after the install, (the 50 year old slab on grade presumably had no V.B.) and the adhesive failed. It was just one classroom in a school that we put the rubber tile down as a test floor to see if we wanted to use it elsewhere to minimize stipping and waxing expenses for the district. The adhesive issue answered the question for us long before we got to determine the advantages of the rubber (if any). We went back with VCT and a High RH compatible adhesive and 8-10 years later; no issues. We are not sure if RH testing would have given us a better idea of how much moisture movement we were getting in the slab or not but it appears that clearly this is a location that has a large flucuation of the slab moisture levels depending on the season, weather, etc. Steven Bruneel, AIA, CSI-CDT, LEED-AP, EDAC Senior Member Username: redseca2 Post Number: 394 Registered: 12-2006 Posted on Thursday, April 11, 2013 - 12:40 pm:    "Has anyone specified the testing and everything correctly, and the contractors followed requirements, and yet still had a failure?" We had an "exception that proves the rule" experience about 2000 when the Owner of a large new Medical Office Building called us frantically because floors were delaminating and exhibiting the classic big blisters. The Owner referred to the failure locations by room name and number and it took pulling out the plans to realize that all these locations were in a vertical stack. The Owner, without the Architect's tendency to see these things 3 dimensionally had not even noticed this. I remembered that this was the location of the tower crane. This was an inner city project site with no available space for the crane outside the building footprint. These pieces of concrete deck had been put in way out of sequence late in the project schedule when the building was closed in, and the tower crane was removed. The original steel and concrete subs were long gone and I still am not sure what crack team the General Contractor put together to in-fill these areas. ken hercenberg Senior Member Username: khercenberg Post Number: 499 Registered: 12-2006 Posted on Thursday, April 11, 2013 - 01:04 pm:    Steven, for starters they probably didn't bother with a vapor retarder under the crane slab. Then when they didn't remove the crane slab, part of the problem started. If no one was paying attention, my guess is that even if they complied with W/C ratio and proper curing and finishing requirements at the upper floors, they probably installed finishes too early just to get the work done. Of course there's no way to know. Infill 'projects' can be such fun. Steven Bruneel, AIA, CSI-CDT, LEED-AP, EDAC Senior Member Username: redseca2 Post Number: 395 Registered: 12-2006 Posted on Thursday, April 11, 2013 - 02:32 pm:    Ken, The crane footing slab wasn't an issue. That was at the mat-slab level, 90 feet and 6 levels of underground parking below the on-grade first floor. It was wonderful to watch them set up a tall crane set in the middle of a 275 by 125 by 90 foot deep excavation and see a building grow around it, so that by the end you could stand on the roof of mechanical penthouse and almost touch the underside of the crane boom. The flooring failures occured on floors 5-9 above grade as I recall. One the 1st and 2nd floors there were public spaces with stone tile that wouldn't have been affected and we probably just lucked out on others that didn't fail by giving them just enough time to dry enough in the now fully conditioned building.