Purpose of high performance lightweight concrete utilization is to reduce cost or enhance functionality of the structure or the combination thereof. The economy of high performance lightweight concrete is discussed.
One might argue that, the production of high performance lightweight concrete is greater than that of normal weight concrete. However, it should be known that the increased cost would not surpass 1%. This increased cost would be easily offset by other economical superiority that high performance lightweight concrete offers.
Fig.1: High Performance Lightweight Concrete
Economy of High Performance Light Weight Concrete
The economy of high performance lightweight concrete is explained through the following points:
1. It reduces dead load of superstructure and hence the foundation would receive smaller loads. As a result, the size of foundation would be smaller, lesser number of piles are required, smaller pile cap will be needed, and lastly, fewer reinforcement ratio will be used.
2. Because of dead load reduction, smaller sizes of superstructure members such as beams, columns, deck, girder, and piers will be needed. This will lead to decline the cost considerably.
3. Dead load reduction lead to smaller inertia forces during earthquakes. This will reduce the extent of deterioration that the structure might suffer and hence cost of rehabilitation will be smaller.
4. Comparatively, long spans can be achieved when high performance lightweight concrete is used to construct precast-prestressed members without increasing total mass. As a result, not only fewer columns or piers will be required in the structural system but also lesser joints will be needed which simplify and ease erection process.
It is reported that, the cost of precast-prestressed high performance lightweight concrete delivery is also declined which easily offset the increased cost of using high performance lightweight concrete.
5. High performance lightweight concrete allows easy movements of marine platforms when they moved out of dry docks and move through shallow water channels. This is because high performance lightweight concrete lead to increase top side loads and decline draft of the structure.
6. High performance lightweight concrete increases fire resistance of concrete members. That is why the thickness of slabs can be declined and hence considerable volume of concrete can be reduced as well.
7. In the case of bridge structure repairing, the deck of the bridge can be widened using high performance lightweight concrete instead of existed conventional concrete without increasing total loads and other elements of the structure.
This is considerably significant since the capacity of the bridge is increased which is crucial aspect of this type of concrete from economical perspective.
8. Due to that fact that high performance lightweight concrete reduces dead load of the element, then it is possible to increase concrete cover over reinforcement bars which increase the durability of the structure.
Subsequently, the structure would require less frequent maintenance which is another economical advantage of high performance lightweight concrete.
9. Thermal insulation is another important property of high performance lightweight concrete which is considerably significant especially for thermal sensitive structures such as hot water storage, petroleum storage or building insulation.
This property might make the structure adequately thermal resistant or if higher degree of insulation is needed, then the cost of insulation application would not be that much if conventional concrete were used for the construction of the building.