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Wednesday, November 23, 2011

Promotion Partner; Riverkeepers

Looking for local partners to promote pervious concrete? Don't forget about your local Riverkeeper. Like us, Riverkeepers are dedicated and passionate about clean water and are always looking for opportunities to educate the public about clean water issues. Recently I worked with a local Riverkeeper, the Upper Chattahoochee Riverkeeper, to design a new flyer entitled “Pervious Pavement; Solutions for Sustainable Development”. You can download it here: http://www.npcpa.org/#!__reg

This flyer is a great resource for counties, municipalities, and developers in the Atlanta marketplace and it comes from our Riverkeeper, a steward with a very powerful voice.

If you want to find the Riverkeeper in your area, go to http://www.waterkeeper.org/ht/d/OrgDir/pid/210

Thursday, October 13, 2011

Who says that concrete isn't inspiring?

A poem by Jim Lafond-Lewis.

___________________________________________________________________

Every organization or loose association of people ought to have its poet laureate.

I would like to be poet laureate of the Pervious Concrete Association.
I would meet regularly with the members and the witch doctor.
We would all feel safe and uplifted
or grounded together.
We would mingle in the lobby before meetings.
I would dream enough for all of us,
especially during discussions
of the Maine Department of Transportation's RFPs.
I would draw attention to the sight and sound of ME DOT RFP
and the doctor would conjure the rumble a small airplane would make as it
rolled across a pervious runway in the rain.
Where once it would have been grounded, bogged down in mud,
my poetry will rise off the concrete and fly across Penobscot Bay!
 
____________________________________________________________________
 
To read more of Jim's poems go to his page:
 
A Wrinkled Man - Un Hombre Arrugado

Tuesday, October 4, 2011

Design for Pervious Concrete

The next design class will be held at Southface, Atlanta, GA. If you are interested in hosting a class in your area, let me know.

Monday, September 26, 2011

How Much Pervious?

I’m constantly asked how much pervious concrete is being placed in the US on a yearly basis and I typically respond with “I have no idea”. As I’ve retired from contracting, I haven’t been in the field for the past few years, so for while I lost touch with the market. However, I’ve been working for the Association for a full year now, and what started out as getting a call every other week from someone looking for help on a project, has now become a daily event, at least one call on a pervious concrete project every day. I get so many now that I don’t have time to respond like I used to and I have to direct them to the website to find a contractor.
I’m sure part of this is due from awareness that the Association exists, but the major reason is that the pervious market is exploding. It’s not just the number of jobs I get calls about; it’s the size of them. During the last two months, just three of these projects alone (one in the SE, one in CA, and one in the NE) total over 4 million sf. Never before have I seen the number of projects planned and projects of this size. Will 2012 be the year we top 10 million SF?

Thursday, September 22, 2011

ASCC Annual Conference

Last week I had the privilege of presenting "Troubleshooting Pervious Concrete" to the American Society of Concrete Contractors. I am very impressed with the quality of ASCC and encourage pervious contractors to get involved with this group.

Thursday, June 16, 2011

Proper Equipment for Pervious

What is proper equipment for placing pervious concrete? I you asked me that question 25 years ago I would have said a 2x4 screed. The first time I worked with pervious, in the spring of ’86, that’s what I used; a 2x4 magnesium screed. In fact, we would routinely hand rod pervious, using a hand float as a spacer to strike high and then follow with a static roller for compaction. We quickly learned that a truss screed was a much easier method for larger placements, but we still did our tie-ins by hand with a spreader, a large flat rake. Some jobs were so chopped up, especially when working around trees or on varying slopes, we would use a spreader on the whole job and follow with just a narrow cross-roller.


That is pretty much how it was done until about eight years ago. There were some other contractors trying plate compactors, but as it required placing a really dry mix, and I have always felt that more moisture was needed not less, I stayed away from that technique. Around eight years ago, I started working with a Bunyan roller screed and that became my new normal. David Mitchell w/ Bunyan had been trying to get me to try his screed for years but I had a pretty narrow mind as equipment was concerned. My hesitation to try the roller screed can be blamed on two things; 1) the type of mixes we working with; drier, pound into place mixes and 2) my idea that there was only one “best way” to do things.

As admixture companies began developing new products for pervious and making the mix more fluid; the options for equipment choices grew and I soon realized that there are many “best ways”. To explain what I mean, consider the debate of “prescriptive vs. performance”.

At its core, the idea behind “prescriptive” is that there is one “best way” to accomplish the goal. The problem with this idea is that this is not necessarily true. In fact, we spend a lot of time trying to get designers to go to performance based specifications because we know we can reach the goal more often without prescriptive requirements limiting our options. The same is true with equipment for pervious. When we “prescribe” the equipment, we lose focus on performance and we fall into the same trap that prescriptive designers find themselves. We say “they want their cake and eat it too”. Well now we know how they feel. It’s a tough choice, but we have to choose whether we want to control how to do it, or else set the standard for performance. And speaking from experience, the installers will figure out how to get it done with their equipment if we give them clear defined goals.

Today, there are even more equipment choices out there. Lura makes a lighter aluminum roller screed, Somero makes a pervious concrete head for the laser screed, and who knows what tomorrow will bring concerning pervious equipment, mixes, admixtures, uses, etc. By limiting options we can literally hold pervious concrete technology back, but by focusing on performance, we can allow pervious concrete technology to continue to advance and become an even better product.

So what is proper equipment for placing pervious concrete? Today, I say whatever gets the job done.

Wednesday, June 15, 2011

Auburn University Continuing Education

The first Auburn University Continuing Education class, “Design for Pervious Concrete”, has been scheduled for July 15, 2011 in Atlanta at the Georgia Association of Water Professionals. The program description is as follows:

This one-day program will provide participants a detailed understanding of pervious concrete stormwater systems and its use as a low impact paving alternative. It will discuss issues affecting successful design with pervious concrete, including mix design, sizing, hydrology, siting, site preparation and post placement landscaping, layout, certain aspects of placement execution, and long term care and maintenance. The course includes two workshops; in which the participants form teams and design and specify a pervious concrete stormwater system. This course should be of direct interest to those in the Civil Engineering and Landscape Architecture fields, including county engineers, city engineers, public works officials, transportation engineers, DOT personnel, consultants, and all those with responsibilities for stormwater design and control.

The course will soon be offered around the country.

For those of us who are promoters of pervious concrete, this course is a "must attend" as it is one of the required courses for “Pervious Concrete Professional” designation, a credential that identifies someone who has advanced knowledge of all aspects of pervious concrete. Design for Pervious Concrete was developed through a partnership with NPCPA and Auburn University and will be offered in various cities throughout the country. Each class will have instructors provided by both Auburn and NPCPA. Recently I sent out a request for instructors and received good response, but more are needed. If you have experience in teaching pervious concrete programs and would like to help, please contact me.

Wednesday, May 18, 2011

Stormwater: What’s the Big Deal?


Sometimes we get so caught up in our own world that we lose sight of other's perspective. I was reminded of this last week while meeting with the Upper Chattahoochee Riverkeeper along with Jimmy Cotty, Executive Director of the Georgia Concrete & Products Association. Jimmy suggested that we refer to pervious concrete formally as a stormwater system instead of a pavement system and instead of having a specification for Pervious Concrete Pavement, we should have a specification for a Pervious Concrete Stormwater System. I thought this was an interesting proposal because it really focuses on the perspective of those concerned with stormwater. Then I began to wonder if we really understand the perspective of the stormwater professional?

To illustrate this, let me relate an experience I had in 2009. I was invited to Seattle, WA to help write a pervious concrete guide document for Puget Sound in association with the Puget Sound Partnership and Washington State University. This was my first time to the Pacific Northwest and I was looking forward to spending a few extra days as a "turista" and seeing the natural beauty of the Puget Sound. So, after my release from the committee work in Tacoma, I headed north through Seattle and took the ferry across Puget Sound and made my way to Kingston. I was awestruck at the beauty of it all. Yes, I was on a boat and that contributed to my positive experience, but the fact is the Puget Sound is truly a treasure.

Of course, as a proud tourist, I grabbed as many brochures of the area as possible and I also took note of any newspaper articles concerning the Sound, especially anything concerning water quality. Now keep in mind that I am from Atlanta so I had a pretty good excuse for my ignorance of the issues facing the Puget Sound, although it didn't take me long to discover the issues. Each morning, on the front page of local newspapers, there were reports concerning the Sound and its precarious condition. There were stories about oysters not reproducing, a story about toxic chemicals, even one about the "Tacoma Aroma". There was also a story about the $50 million budgeted yearly to stop pollution from entering the Sound, mainly from stormwater, and how more was needed. It was evident to me that the locals had a pretty good assessment as to where the Sound was and where it needed to be as it relates to its wellbeing.

That's why I was surprised by the responses I received from locals when I asked their opinion as to the health of the Sound. Most seemed to be unaware of any threat to Puget Sound.

Consider this...every year, roughly 52 million pounds of toxic chemicals are washed into the Puget Sound from such things as cars and boats leaking oil. To put this into perspective, the equivalent of a Exxon Valdez size oil spill is taking place every eighteen months in the Puget Sound. Congress has created a special Puget Sound office within the EPA with its main emphasis on trying to get a handle on controlling stormwater runoff into the Sound.

So what about you. Are you aware of the stormwater issues in your area? If you are involved with pervious concrete in any way, I encourage you to reach out to stormwater professionals in your area and support their initiatives. It's an ideal way to gain their perspective.

Wednesday, May 11, 2011

New Ways to Cure Pervious


Curing pervious concrete is no doubt one of the most critical aspects of a successful placement. Historically, the curing has been done with plastic sheeting covering the pavement for 7-10 days. For lack of a better alternative, this method is the standard even though it comes with many disadvantages. One of the main downside to using plastic sheeting is the amount of plastic that goes into landfills. For every SF of pervious concrete cured this way, 1.2 SF of plastic will be used. Yes, recycling is an option but we have to admit that hardly no one (if anyone) recycles their plastic. Every once in a while, if the plastic is not damaged, it will be reused but eventually it gets thrown away.

Then we consider the placement restrictions that plastic sheeting puts on the installer. Use of the plastic forces the installer to pour in strips and produces all those construction joints, by far the hardest joints to keep from raveling. Some feel these joints have poor compaction and some feel they have insufficient curing, but whatever the cause, I say minimize the joint and you'll have less problems. And of course we need to consider the labor costs and impact that plastic curing has on the project schedule. At least one week after placement, someone has to remove the plastic, and this phase of the project is stalled for the curing week. Although no traffic should be allowed on the pavement, sawing and/or stripping could take place during the curing phase if not for the plastic sheeting. Again, many disadvantages.

Thankfully, there are other ways to cure pervious that I expect will soon be available if not already. Here are some that I am aware of:

One manufacturer is developing a biodegradable plastic curing sheet for pervious concrete. One manufacturer has developed a sprayed on curing compound combined with a densifier for improved surface durability. Many are aware of the internal curing admixture that I have been using for years but also saturated lightweight sand is being used in pervious concrete for internal curing (expect ACI report on internal curing soon).

Using these curing techniques individually or combined should prove to be an advantage to pervious concrete, providing the benefits of curing without the disadvantages of traditional plastic sheeting.

Friday, May 6, 2011

Pervious Concrete Needs _______?


What is the number 1 need for pervious concrete right now? Training for installers? Training for producers? Better tools? Better standards? Better Design? More testing? More environmental laws? Better economy?

What do you think? Give your thoughts on this at the NPCPA LinkedIn site. linkedin

Thursday, March 24, 2011

Infiltration Fabric for Pervious Concrete

This week at ConExpo/ConAgg, Propex announced the introduction of a completely new class of non-woven geo-textile: PERC Pervious Concrete Infiltration Fabric.

According to Propex, PERC is specifically designed to assist in the effectiveness of pervious concrete applications with enhanced water flow properties and permeability, but with low pore size to trap soil. Made from 100% recycled PET from soda bottles, the fabric's smaller pores restrict dirt and particulates from contributing to clogs, which reduces maintenance in storm drains.

Most contractors are aware that some sort of fabric is needed to maintain separation between the softer, less compacted soil base and stone filter layer, however, sometimes there is confusion over what fabric to use for pervious concrete applications and where to buy it. Now contractors and installers can order it right from their ready mix supplier and have it delivered to the site.

This is great news for pervious concrete systems but what really excites me are the tremendous growth implications for designers using LID strategies. There have been attempts to use aggregate gradation to maintain structural integrity of the system, which is easy enough to design but impossible to construct. The fabric is engineered to provide structural support to the pavement, while allowing stormwater to infiltrate, but it also has the ability to "wick". Technically this is referred to as "capillary action". It is the same process that allows water to go up a tree to its leaves. For projects that have pour soils, this is big news.

When rain falls on these projects, very little is infiltrated unless the site is perfectly flat (and sites are never flat). Imagine a site with soils that drain at 0.1" (one tenth of an inch) per hour. This is a soil that we would basically call non-porous. Especially when the rain that comes in contact with it runs on down the slope. The trick is getting the water to maintain contact the soil long enough for infiltration to take place. Historically, hard to do, but now, very easy. The fabric will literally pull the water against gravity and spread the stormwater up the hill, maintaining contact with the soil for infiltration over the whole site. That means a site with these poor soils will infiltrate 2.4" per SF over a 24 hour period, even on a slope! I watched a demonstration of this capillary action and saw the water go up a 60% slope!

Use of this fabric will help increase the market for pervious concrete in areas with soils that infiltrate less than ½ inch per hour and the kicker is it is made with 100% post consumer recycled content. Each roll of PERC uses 3,350 plastic soda bottles. And no, color is not added. Green is its natural color.

Friday, March 18, 2011

Good Observations

Today I had a Producer send me an email about a project that was just completed. It's good to find Producers that care enough to go back and look at the job with the goal of improvement.  His observations/comments were as follows:

"Now that the poly has been removed I went and walked the parking area that the installer placed (about 1000 yds. 8" thick). The overall pavement looks very good with the exception of two items: 1) There was a lot of hand work (adding additional material and hand tamping) at the edges (construction joint) of each lane. This left an overall darker appearance highlighting each lane (maybe 18" wide). This area also concerns me for potential raveling as evidenced by some loose aggregate. 2) The saw joints did not originate at the joints in the curb and also were not continuous across pavement. Some of the cuts went through 2 lanes then was offset by several feet and resumed. There is one crack in the lower area of the pavement originating at a sewer manhole cover. This is not an official report, just thought you would be interested. Again the mix looks like it will perform very well and the placing and finishing work looks very good for the main part of the lanes. Maybe some education on treating the construction joints and developing a joint plan is in order."

These are good observations that could probably be seen at many sites around the country, and yes, more education is needed.

I'll address these two issues in upcoming blogs, working edges and installing joints.

Monday, February 21, 2011

Lunch & Learn Prime Time

Is there such a thing as the "Prime Time" for a lunch & learn? I think I may have discovered it, the optimal time for a L&L! And what's more, I'm not talking about going to the client's office. No,no, during "Prime Time", they'll come to you. And be careful how many you invite as they all may show up!

If you are a promoter, you are well aware of the basic lunch & learn formula;

Attendance = Topic X Interest + Free Food / Schedule

Or you could say that no matter the topic, interest or food, the schedule is the critical factor. That is why we promoters go to the clients for their L&Ls. If you've ever tried to get them to come to your office for a L&L, you know how hard it is. Some of us reason that if you have a really good topic or if you have really good food you can get them to come. I've tried it and it doesn't work. Once I had a group of 20 that wanted to learn about pervious concrete and they all loved sushi, so we had $500 worth of fresh sushi delivered for a pervious party. 2 showed up. I learned my lesson, and from then on I've been doing the deli sandwiches at their offices, just like everyone else.

And then I discovered the "Prime Time".  I was part of a L&L where we invited a local water professional association's stormwater committee. We expected 20 or so and how we were surprised when 78 showed up! For pizza at that!

So when is this "Prime Time".  Look on your calender and find a Monday that is a Holiday and schedule your L&L for the Friday before. It's as simple as that. By the time the L&L is over there isn't enough time to go back to the office, so they'll "just go back to work on Tuesday".  From their perspective, this is the perfect way to begin a long weekend!

Give it a try and let me know how it works.

Monday, February 7, 2011

Call for Instructors

Auburn University (AU) and the National Pervious Concrete Pavement Association (NPCPA) is seeking qualified professionals to provide classroom instruction in the Design for Pervious Concrete (DPC) program offered Nationwide. Qualified instructors must have experience in the design, construction or production of pervious concrete. It is expected that qualified instructors will be offered the opportunity to provide between four and eight full days of training in the calendar year for the DPC program. By becoming a DPC approved instructor, an individual can gain increased visibility among practicing professionals, access to a network of fellow instructors and teaching resources, and the opportunity to earn CEU's.

Those interested in becoming a DPC Instructor should submit their qualifications, experience, and honorarium requirements to NPCPA. For more information, please contact me at:

dfisher@npcpa.org
770.309.6649

National Pervious Concrete Pavement Association
125 TownPark Drive, Suite 300
Kennesaw, GA 30144
404.835.7190 P
404.835.7199 F

Thursday, January 27, 2011

Pervious Concrete Mix Design Calculator

The Pervious Concrete Mix Design Calculator was handed out World of Concrete and was a big hit with the attendees.  It assists producers in developing quality pervious concrete mixes based on their local materials.  It is also a good tool for the contractor to compare theoretical vs. actual density (which in effect becomes a yield measurement tool).  If you were not able to pick one up at W.O.C. and want one for yourself, contact me at the following address:

Dale Fisher, Executive Director
National Pervious Concrete Pavement Association
125 TownPark Drive, Suite 300
Kennesaw, GA 30144