From a contractor's viewpoint, self-consolidating concrete sounds like a panacea—a solution for many of the problems typically encountered on a jobsite. With no vibration, it can fill your forms to produce perfect, smooth surfaces. For flat-work, it can flow without segregation for 50 or 100 feet. So why aren't we using it everywhere?
More than anything, I believe it is simply a lack of confidence—and, of course, cost. As a contractor, you have to balance the benefits of using this new material against the very real risk of a foul-up. Will it really flow that easily from every truck or will one truck show up with a stiff mix? Will it blow out your forms if you don't have that fancy, expensive European formwork? Will it segregate, leaving you with rock pockets? Will the extra $50 a yard you have to pay for admixtures really let you eliminate a couple of workers and speed up the job?
In November, the Center for Advanced Cement-Based Materials (ACBM) sponsored a major conference in Chicago on SCC. Virtually all of the 450 attendees were strong advocates for SCC and had numerous examples of where it had solved problems and provided the highest quality concrete. After listening to all this for three days, I had to believe that the day will come when all concrete will be SCC—even zero-slump concrete can be SCC if it consolidates without vibration.
And then there is pervious concrete. Another great idea if it works as well as the proponents say it will. But, again, why should you as a contractor take a risk on something you're not sure of?
The answer to all these questions is education. I emphatically am not encouraging you to use SCC or pervious until you know more about it. In fact, I think you would be foolhardy to gamble on any new material or technique without understanding the construction methods and the challenges.
For SCC, the conference provided a lot of that knowledge, and we will be running excerpts from the proceedings every other month throughout 2006. For pervious, we have just teamed up with the National Ready Mixed Concrete Association to sponsor a Concrete Technology Forum, May 24 and 25, 2006, in Nashville. This two-day event will give you a complete background in the design and construction of pervious concrete.
So do whatever you can to educate yourself. You may end up feeling that the risk is greater than the potential rewards, or you may decide to go for it. Either way, you will be making an informed decision and not simply letting opportunities pass you by because you're too busy or risk-averse. Ignorance, after all, is the greatest risk.
William D. Palmer
Editor in Chief