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Pervious Concrete Tips from Bob Banka Part 5

Top 5 Steps to Successful Pervious Concrete Installations

We asked Bob Banka President of Concrete Management Solutions to answer some important questions in a 5 part series about Pervious Ready Mix Concrete and the best way to get the most out of a pervious concrete installation.

Question:  What are the 5 most important steps for a pervious concrete installation?

Step 5

Well, so far so good!  You read the specs and made suggestions to help the job go smoother such as laying out what the testing labs responsibilities are, I mean, what sense is there is making cylinders right?  Better to have unit weights checked to make sure that they are within the +/- 5pcf that they should be. But wait, +/- 5pcf of WHAT?  I was recently on a job where the specs called for the unit weight to be +/- 5 pcf of 125#/pcf.  Well, that might work well in some areas that have stone with a specific gravity of 2.60 but the specific gravity of the stone being used on this job was 2.95 which made the theoretical unit weight around 135 #/pcf.  These kind of things need to be addressed before a project starts, you would hate to start tearing out concrete because the spec was wrong, right?

You did a test pour and made sure that the mix was workable.  Wait a minute, you didn’t?  You showed up on the job and the mix was full of aggregate/cement balls?  You had to add how much water to the load?  The concrete was how hot?  Test pours are that important.  There is no need to start a job until you are sure that the ready mix producer can produce good quality pervious concrete and your crew knows how to put it down, finish it and cover it up. Sadly, many jobs are done twice because this simple step is not taken.

But these things didn’t happen to you.  You did your homework and went into the job well prepared.  Your crew did a fine job of placing the concrete on the ground.  The mix performed well and they hydration stabilizer did its job.  You stapled the painters’ poly to the forms right away and then rolled the concrete at the right time and then covered it with the 6 mil poly after tooling in the joints. You made sure that no matter how hard the wind blew, your plastic sheeting would continue to protect the concrete for the full 7-10 days.

The following week you went back to the job and removed the poly and the job looks spectacular!  Then you did the best thing you could do for the pervious concrete.  You or your lab performed A.S.T.M.     C1701, the standard test for the Infiltration Rate of Pervious Concrete.  You reported in writing to the owner what the infiltration rate was and told them that you would be back in six months to do the test again and help them develop a proper maintenance plan for their site and reminded them that you would be doing this every six months for two years.  What customer service!  The owner has no idea what they will need to do and before the job, neither do we. Every site is different and will need different levels of cleaning and maintenance.  If you get the same readings in two years as you did when the pervious was first put into service, then whatever the owner is doing is working.  If you went from 450 inches of rain per hour to 48 inches of rain per hour then something is not working and adjustments need to be made before YOU and the ready mix producer get blamed for a job that did not function as designed for it’s life.

I wrote about testing and maintenance earlier in this series but it is so vitally important that it bears repeating.  One good job will sell another job but one bad job can cost you and the industry many jobs.  Help the owners protect your reputation and your work and do your follow up.  Pervious concrete may be the next best thing since sliced bread but we as an industry have to do our part to do a great job every time.

Bob Banka is President of Concrete Management Solutions and has been involved with the development of pervious concrete for over twenty years.   To learn more visit:  http://www.perviousconsulting.com