The U.S. Census Bureau projects the value of construction put in place in 1999 will slightly exceed $700 billion. What share of that number does concrete work command? And what is the size of the different market segments?
For more than 50 years, concrete finishers have been warned about the dangers of using tools or methods that densify and seal the concrete surface before bleeding has stopped.
The benefits of well-cured concrete don't apply to floors that must reach a low moisture-vapor emission rate before floor coverings are installed.
When concrete slabs on grade curl, the curling sometimes has little effect on floor performance. If the total curl is less than 1/4 inch or curling occurs primarily in low-traffic areas or under storage racks, the owner can often live with it, provided that cracking isn't excessive. There are occasions, however, when curling isn't tolerable and repairs are needed.
Will using a thin sand layer under floor slabs reduce subgrade or subbase support, causing cracking and poor joint performance, especially under repeated loadings such as forklift traffic? To gather data to help answer this question, The Aberdeen Group performed California Bearing Ratio tests on three soil samples with varying dry densities.
