Types of Concrete
Precast concrete is concrete cast elsewhere than its final position. Precast construction can be used to produce a wide variety of structural elements such as wall panels, bridge girders, pipes, poles, crash barriers, lift stations, etc. The concrete can be reinforced, lightly prestressed or prestressed depending upon its requirements. Precast concrete elements are typically transported from the plant to the job site through highways, rail, or barges. Tilt-up concrete is a form of precast concrete and is generally referred to as site precasting.
Tilt-Up construction is “a construction technique of casting concrete elements in a horizontal position at the jobsite and then tilting and lifting the panels to their final position in a structure”. The greatest advantage of tilt-up construction over cast-in-place concrete is the ease and speed of construction. Generally the concrete should attain a high early age flexural strength to facilitate lifting and handling. Tilt-up concrete is a form of precast concrete and is generally referred to as site precasting.
Flowable also known as controlled low-strength material (CLSM) is a self-compacted, cementitious material used primarily as a backfill in lieu of compacted fill. The compressive strengths must be lower than 1200 psi and often is lower than 200 psi. Since the material flows into place no compaction is required which is a significant advantage over compacted back fill. Flowable fill can be made with very high amounts of non-standard materials.
Pervious concrete is concrete that does not contain fine aggregate. It typically has a voids content of 15% to 35%. This ensures that the concrete has the unique ability to allow storm water to pass through its mass into the ground underneath. Pervious concrete offers significant environmental benefits as it reduces the requirement for drainage facilities. Further it facilitates the recharge of ground water and the filtration process purifies the water as it percolates below.