Durability design and performance of self consolidating lightweight concrete bridgeport holdings liquidating trust
Besides volcanic ash for making regular Roman concrete, brick dust can also be used.Besides regular Roman concrete, the Romans also invented hydraulic concrete, which they made from volcanic ash and clay.Regular concrete is the lay term for concrete that is produced by following the mixing instructions that are commonly published on packets of cement, typically using sand or other common material as the aggregate, and often mixed in improvised containers.The ingredients in any particular mix depends on the nature of the application.Various types of concrete have been developed for specialist application and have become known by these names.Concrete mixes can also be designed using software programs.In the UK, BS EN 206-1 defines High strength concrete as concrete with a compressive strength class higher than C50/60.High-strength concrete is made by lowering the water-cement (W/C) ratio to 0.35 or lower.
This allows a user of the concrete to be confident that the structure will perform properly.
To compensate for the reduced workability, superplasticizers are commonly added to high-strength mixtures.
Aggregate must be selected carefully for high-strength mixes, as weaker aggregates may not be strong enough to resist the loads imposed on the concrete and cause failure to start in the aggregate rather than in the matrix or at a void, as normally occurs in regular concrete.
Typically, a batch of concrete can be made by using 1 part Portland cement, 2 parts dry sand, 3 parts dry stone, 1/2 part water. For example, 1-cubic-foot (0.028 m) of concrete and would weigh about 143 lb (65 kg).
The sand should be mortar or brick sand (washed and filtered if possible) and the stone should be washed if possible.
In some applications of high-strength concrete the design criterion is the elastic modulus rather than the ultimate compressive strength.