It’s that time of year again, where we tell everyone to use Fritz-Pak Delayed Set in their concrete because it’s too darn hot outside! But this year, instead of reminding you how unbearably hot it is right now, we decided to focus on a new application for concrete set retarders, pervious concrete pavement.
Pervious concrete pavement is exactly what it sounds like; it’s a concrete mix designed to have so many voids and spaces that water can easily flow through. The main application is for stormwater management. One of the biggest problems with runoff water from traditional concrete pavement is that it contains about 90% of all the oil, gas, grease, and other hydrocarbon liquids that accumulate over time from automobile traffic. And that polluted runoff water ends up in our rivers, lakes, streams, and oceans. However, in pervious concrete, that water is now able to flow through to the soil, where aerobic bacteria can safely and efficiently breakdown most of the hydrocarbon pollution.
While it all sounds great, making pervious concrete is no easy task. In order to make concrete that is both structurally sound and extremely porous, you need a lot of cement, narrow graded aggregates, no sand, and very little water. To focus just on the cement, you need about 600-700 lbs of cement per yard, and a water:cement ratio as low as 0.27. The net result is a mix that is extremely tight, highly compacted, and very quick setting. Add in 100 degree weather conditions, and it sounds like a contractor’s worst nightmare! That’s where Fritz-Pak Delayed Set can help.
The Delayed Set works as a hydration-stabilizing admixture, which is a fancy way of saying set retarder. By adding Delayed Set to a pervious concrete mix, you can slow the setting time of the material, which gives you more time to place and finish the pavement. Due to the odd mix design and application, the dosage rate of Delayed Set is actually much higher than you would expect. The typical dosage rate is about 4-6 oz of Delayed Set per 100 lbs of cementitious materials, which should only result in about 30-60 minutes of set delay.
Make sure to use Fritz-Pak Delayed Set on your next pervious pavement job, or on any concrete job this summer!
If you have any other questions about pervious concrete, feel free to visit www.perviouspavement.org.
Fritz-Pak Corporation is a member of the American Concrete Institute, the National Ready Mixed Concrete Association, the American Society of Concrete Contractors, including the Decorative Concrete Council, the American Concrete Pumping Association, and the International Packaged Concrete Manufacturer’s Association