Equipment World Digital Magazine
Issue link: http://read.dmtmag.com/i/726012
EquipmentWorld.com | September 2016 65 road science | continued Plants need to have an assort- ment of aggregate gradations, in- cluding coarse, intermediate, and fine. "I think getting well-graded aggregates is the most cost ef- fective way for a concrete paver to consistently deliver and place high quality concrete pavement," Wathne says. Admixtures The concrete paving indus- try has been criticized for its seemingly increasing reliance on performance-enhancing admixtures. "Along with these various admixtures, when we also use supplementary cementitious materials like fly ashes or slags, sometimes incompatibilities can develop that cause the concrete to react in unexpected ways," he says. And some admixtures are sensitive to extreme ambi- ent temperatures or too-wet aggregate. "You then have outcomes you would never anticipate," Wathne says. "It's just a more complicated system. In the past, we didn't have these tools available to us, so we ended up with mixtures that performed fine, but they were probably not optimized." Performance troubleshooting When a pavement isn't per- forming as it should, a contrac- tor may first feel he should contact the paver manufacturer. The first thing the manufacturer will do is ask about the mix qualities. In addition to the aggregate gradation, contractors must also look at the design of the mix and the proportioning. The de- sign establishes the concrete's strength, intended purpose, and environment. This means contractors must scrutinize what they are de- signing, the proportions of the mix, and other specifications to determine if they can expect it to perform properly. "A lot of it has to do with uniformity as well," Wathne says. "You're paving day in day out and it's a tough environment out there because the weather and material changes." Contrac- tors have to constantly adjust for all these variables in their pav- ing operation so that a uniform, smooth product comes out of the paver every day. CONCRETE RESULTS with unmatched precision E-Z Drill is ready for any challenge. Airport runways or roadways. 100 holes or 100,000 holes. Our drills off er unmatched reliability, effi ciency and precision. Complete any job on time and on budget. GET RESULTS. GET AN E-Z DRILL. ezdrill.com 1-800-272-0121 THE YELLOW DRILL WILL (continued from page 61)