Normally, steel bars are used as reinforcement for concrete pavement. For jointed plain concrete pavement (JPCP), steel dowels are used to connect the concrete pavement panels. While, for continuous reinforced concrete pavement (CRCP), a continuous steel reinforcement layer (two direction mesh) is placed near the middle depth of the concrete slab (the common slab thickness is 250 to 275 mm). However, joint distress in the existing JPCP is caused potentially by excessive stress concentration of steel dowel bars, stiffness mismatch between steel and concrete, and possible corrosion of steel leading to joint spalling. In addition, improper functioning of a joint may cause pumping of water from pavement bottom leading to larger voids under the pavement and consequently resulting in possible corner break. This encourage most Ministries of Transportations (such as MTQ and some DOTs in USA, e.g. Texas and West Virginia) to choose the use of CRCP. However, with CRCP, the problem of steel corrosion is still unsolved. Moreover, for toll-fee roads, an automated method was developed to collect the fees from passing vehicles without interrupting the traffic. But this method require that the pavement of the road posses a neutral electromagnetic properties, which is not available for steel bars. Glass FRP reinforcement is a very attractive alternative to steel in this type of application as it already posses these two properties (non-corroding and neutral electromagnetic). The thermal and stiffness compatibility between GFRP bars and concrete is an added advantage taking into account that shrinkage and thermal stresses in concrete have been known to be the principal factors for the incipient cracking in concrete pavements and bridge decks. The thermal stresses in the concrete pavement are developed because of the restraint provided by the reinforcement (bond characteristics) and the friction from the sub-base under the concrete pavement. The approach to this new research opportunity is to investigate the GFRP reinforcement ratio and configuration (bar diameter and depth of the reinforcement layer) through laboratory testing, analytical studies (FEA), and field applications.
Precast reinforced concrete pressure pipes are used for pipe lines to carry liquids. The size of these concrete pipes ranges from 0.3 to 3.0 m in diameter and from 1.0 to 20.0 m in length according to the volume of the expected flow. These concrete pipes can be conventionally reinforced or prestressed with steel wires based on the amount of internal pressure. The problem of steel corrosion arises due to the moisture and chemicals in the surrounding soil. The rehabilitation or replacement of such concrete pipes is very expensive if measured in service interruption and difficult access to deficient locations. The use of the non-corroding carbon FRP prestressing tendons is an excellent alternative. However, the fabrication of these precast concrete pipes (embedded-cylinder type, which is made of a core composed of a steel cylinder encased in concrete and subsequently wire-wrapped on the exterior concrete surface and coated with cement morter) using prestressed steel wires is a very fast and cost effective. The prestressed wire is anchored at one end of the concrete pipe and wrapped helically around the pipe, which is rolling while advancing on the prestressing rig. To realize the use of carbon FRP prestressing tendons as a competitive alternative a better (faster) or at least a similar method (to that of steel wires) should be developed. The approach to this new research opportunity is to investigate the development of an anchoring system for carbon FRP tendons (strips or rods) and the determination of the prestressing level (as a percentage of the ultimate strength) through laboratory testing, analytical studies (FEA), and field applications.