Bruce A. Suprenant

Bruce A. Suprenant's Posts

Common Problems with F-Number Measurements

Common problems in F-number measurement arise on many jobs. Following ASTM E 1155 "Standard Test Method for Determining FF Floor Flatness and FL Floor Levelness Numbers," is essential. Read more

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Testing a Petrographer's Conclusions

During the summer of 1999, a concrete contractor placed an exterior parking lot for a commercial building in the Midwest. The concrete was air entrained and received a broomed finish, followed by 3 days of moist curing with plastic-coated burlap. Because some of the concrete set at a different rate than the surrounding concrete, the appearance of the broomed finish wasn't uniform and "soft surface conditions" were reportedly exhibited. The parking lot owner questioned the quality of the concrete, and had cores sent to a test lab. The petrographic report stated that the coarse aggregates were generally sound but the entrained-air content in the top 1/4 inch of the two samples was inadequate to resist freeze/thaw damage. The petrographer further concluded that freeze/thaw damage was expected to be a problem for the concrete slab. Read more

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Double Dose?

In structures for which rebar corrosion isn't an issue, calcium chloride is the most economical and effective accelerating admixture. It's widely used in a liquid solution in unreinforced pavements, residential foundation walls, and floors placed in cold weather. It helps concrete set and gain strength faster, allowing finishers to complete their work sooner and decreasing the likelihood of damage caused by early freezing. Read more

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Long Wait for Lightweight

Many building owners and contractors have reported experiencing project delays while waiting for slabs made with lightweight concrete to dry to the moisture-vapor-emission rate typically required by floor-covering manufacturers (3 pounds per 1000 square feet in 24 hours). Though we couldn't find any data regarding the drying time of lightweight concrete, field experience tells us that lightweight concrete takes longer to dry than normal-weight concrete. To help fill this information gap, Concrete Construction devised a testing program to find out how long it takes lightweight concrete to dry. Read more

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Concrete Market Y2K

More than 441 million cubic yards of concrete will be placed in 2000. And the total in-place concrete cost? A whopping $88 billion dollars. That's up almost 13% from 1999. We gathered cement and concrete statistical data from several sources. Then, with the help of the Portland Cement Association and R.S. Means, a company specializing in estimating and analyzing construction costs, we developed a methodology for estimating the total dollar value of cast-in-place concrete. We extended the methodology to estimate the amount of concrete placed in various building elements, including footings, walls, slabs on grade, columns, and elevated slabs. Read more

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