Home Depots across the country have one thing in common and that’s the great looking polished floor you see from the moment you walk in. The mix design for this project was like none we had seen before. The specs are the same for every floor whether it be in Iowa, Alaska, or Texas. The challenging part of this mix wasn’t strength or durability it was the aggregate gradation requirements. Each sieve had a certain amount of passing material allowed. We tried numerous sources, sizes and proportions to meet this strict criteria and every different trial was becoming too time-consuming to meet the deadline for the mix approval.
We ended up writing a Microsoft Excel program that would perform the calculations at a fraction of the time we were able to do it by hand. In doing this we were able to go through a vast amount of different ideas in a matter of minutes. We ended up doing a mix design that required four different aggregates ranging in size from 1.5” rock down to 3/8” chips. The engineer assigned to Home Depots across the country said our mix design met the specs better than any other mix in his experience. Here in central Iowa, we have some of the best concrete aggregates available to us than many other markets in the U.S. Couple that with the ingenuity we applied to this project by creating a program that helped aide us in fine-tuning mixes in a matter of seconds, and it’s no wonder we achieved the best mix design the engineer had ever seen. We still use those programs today as many specifications are leaning toward gradation targets as a means of increased strengths.