density
No matter the method by which it is applied, concrete is a fascinating material. The history books tell us that it's been in use for thousands of years - as far back as 6500 BC, when it was used by Bedouins to make cisterns in which they collected and kept water underground in desert climates. The ancient Greeks used concrete, too, as did the Assyrians and especially
In the world of concrete science and application, innumerable variables have an influence on whether a concrete installation is successful or not. These include but are not limited to the skill of the applicator, the suitability of the mix design, the temperature at the time of application, the equipment used, the water-to-cement ratio and the size of the aggregate. For all the seeming complexity, however, the nature of the material itself invests the process with a few immovable facts. One of these directly undermines the swimming pool industry’s “standard” that calls for a compression strength of 2,500 pounds per square inch for pneumatically placed concrete (that is, gunite or shotcrete). It’s not because the standard is inadequate per se; rather, it’s because
