Traditionally, bridge abutments have always been a problem for the construction industry. They pose many challenges during their construction and can significantly delay the time needed to complete the whole project. Aggregate compression under the bridge can be one of those problems. Under normal circumstances, sand is typically used to mitigate this problem. However, this may cause excessive pressure on the side walls, which usually forces the designers to increase the wall thickness, so that they can withstand the weight imposed by the sand. Without this procedure, the lateral forces imposed by the sand could cause the bridge to fail prematurely.
All of this causes many problems, the biggest of which is, of course, money. Thick walls, expensive infrastructure can be very costly and time consuming to build, but also very costly to maintain. Another possible solution is to build the bridge using traditional materials only. There are two main areas that may pose a problem in this scenario. The first is that the soft ground upon which the bridge would be based can eventually compress, causing subsidence, that would lead to significant cracking in the structure of the bridge. The weight imposed by the aggregate on the soft ground is the reason for this phenomenon. The second problem is that the aggregate itself can also subside also causing the problems described above.
These problems can be aggravated even more if building on softer grounds such as peat, for example. All of them can however be reduced using foam concrete. The major benefits of using it are: lower labor costs and much shorted construction times. The biggest advantage foam concrete has over other materials and methods is that it can be adapted to specific requirements of a particular job. It is therefore an extremely versatile material. By selecting the right combination of source materials it is possible to achieve properties that fit the design as well as possible. Adapting foam concrete to local conditions is very easy, which permits the design team to have as much freedom as possible.
– Loose aggregate is known very well for settling into soft soils. A very good method for eliminating this problem is simply using foam concrete in its place. The reason why it is a better material is that it is a continuous surface, that is not broken up into many pieces. This allows the material to distribute the weight across the whole surface area, which eliminates the problem of settling into soft ground.
– With sinking and settlement virtually eliminated, road subsidence is not a problem as well. Therefore, the amount of work necessary to maintain the bridge after it has been build is significantly reduced. Because of this, the total operational cost during the lifetime of the bridge is also drastically reduced.
– The lateral forces imposed on the side walls are reduced, thus making it possible to build much thinner walls, meaning much lighter foundations. The savings that can be achieved using this method are immense.
– Because foam concrete has load spreading capabilities, it is possible to pour the material gradually, with each larger poured on the of the previous being stronger. This allows significant cost savings, as the bottom layers do not need to be as strong as the top ones. This is achieved simply by using less cement while pouring the bottom layers, and using less while pouring the top ones, which will carry more weight.
It is clear that foam concrete not only offers excellent performance, but also cost savings. It allows the design team to use less pillars than traditionally and allows the contractor to complete the project faster and cheaper.