Ready Mix |
|
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
Lightweight Concrete |
|
Lightweight Concrete for structural applications refers to concrete with a density of 90-115 lb/ft³ compared to normal weight concrete of 140 - 150 lb/ft³. The concrete strength should be greater than 2,500 psi. The concrete is made with lightweight coarse aggregate and is air-entrained. Some or all of the fine aggregate may also be lightweight. Since these aggregates absorb moisture at a greater rate than other aggregates, pre-wetting is required. Typically, lightweight concrete is used to reduce the dead load of a concrete structure, which allows the structural designer to reduce the size of columns, footings and other load bearing elements. The mixes can be designed to achieve similar strength as normal weight concrete. Structural lightweight concrete provides a better fire rating and with its higher R value also provides better insulating qualities for wall elements. Usually the slightly higher costs of lightweight concrete are offset by the size reduction of structural elements, the need for less steel reinforcement and a lower volume of concrete, which lowers overall costs. Lightweight structural concrete has been used for bridge decks, piers and beams, slabs and wall elements in steel and concrete frame buildings, parking structures, tilt up walls, topping slabs and composite slabs on top of metal decks. Based on information from the National Ready Mix Concrete Association CIP series #36. |
|
