The concept behind the "TCP" design is that each slab of the pavement is loaded by only one wheel or a set of wheels at the same time. This significantly reduces the top tensile stresses of the slabs. With this configuration of loads versus the dimensions of the slab, the cantilever effect is reduced by the rocking of the slab as the load moves over it, so each slab supports the loads under the wheels, supported on the ground.
To achieve this condition, it is necessary to dimension the slabs in such a way that with a given truck; each wheel, or a set of wheels, loads a different slab at the same time. As different types of vehicles exist, it is designed for the most harmful, unless the traffic is known and then it is designed for the type of vehicle that will use the road
Reducing the stresses on the top of the slab allows for a longer lifespan of the pavement, or seen from another point of view, it allows a reduction of the thickness to achieve the same stresses and lifespan obtained in the traditional design. It is with TCP® Design where the top stresses generated by the loads are smaller, so the pavement can be designed with thinner concrete slabs.
This can be represented by the following figure of stresses at the top of the slab, for different geometric configurations of the loads respect to their dimensions. Using ISLAB 2000, we can model different configurations of loads versus sizes and geometries of slabs. All other variable (Soil, LTE, Temperature Gradients, etc) are kept the same.
Comparison between slab sizes optimized with the load geometry and the thickness needed to achieve the same tensile stresses
Pavements designed and constructed with the TCP technology are thinner compared to traditional designs, for similar loads and traffic.
Besides the lower initial cost, these pavements have the typical performance of traditional concrete pavements and thanks to the development, some aspects have been improved.
TCP technology allows increasing the total area built in more than 20% compared to traditional design.
The main benefits over asphalt pavements are:
The objective markets are the public organizations, concessionaires and contractors, related to pavements for roads, highways, industrial pavements, rural roads and urban streets. As a reference this technology is interesting for:
“Improved concrete pavement slabs for streets, roads or highways and the methodology for the slab design”.
This invention is protected in Chile by the Industrial Patent N° 44820, in EE.UU. by the patent N°7.571.581, and worldwide by means of request PCT N° PCT/EP2006/064732 on the World Intellectual Property Organization (WIPO), in addition to other countries of America and Asia.
The TCP® technology is protected in a total of 80 countries, the vast majority with formal grant of the patent, and in others with provisional protection (patent pending).
Ultra-Thin Concrete Pavements (U-TCP) are an extension of the TCP® system. These pavements, besides being composed by short slabs, incorporate structural fiber in the concrete. These kind of pavements are placed directly over the terrain, without sub-base, on roads where the subgrade is in a high level of compaction due to the traffic of cars, trucks and machinery.
To design this type of solution with software OptiPave2®, five separate tests of pavements sections were conducted on different places. The thicknesses of concrete pavements tested ranged between 6 and 12 cm (2.36 to 4.72 inches). With the results of these tests, different conclusions were obtained about the behavior of this type of pavements, which were compared with the theoretical results delivered by the design program OptiPave2®, thus allowing the program to calibrate this type of solution. The tests sections were:
The addition of structural fibers in concrete improves some aspects of this, such as a more controlled cracking and improvements in ductility. With structural purposes, it is pretended that the addition of fibers provides more fracture energy, thereby increasing fatigue resistance and durability of the elements or reduction of the traditional reinforcements. There are different types of fiber, depending on the material, size, shape and diameter.
Manuals, guides and Codes
The TCP design is a revolutionary methodology that considers the positions of the truck loads on the slabs, allowing philosophical changes in the design of the structure of the pavements.
This design, dimensions the slabs in a way that they are never loaded by more than one set of wheels of the vehicle, producing significant reductions on the top stresses in the slabs.
The systems can be used in highways, rural roads, urban streets, industrial pavements and parking lots, in different climates and geographical conditions.