The paper presents the results of experimental and analytical studies concerning the flexural strengthening of Reinforced Concrete (RC) beams using externally bonded cement-based composite like Slurry Infiltrated Mat CONcrete (SIMCON) laminates and polymer-based composites like Carbon Fiber Reinforced Polymer (CFRP) laminates. A total of seven reinforced concrete beams were cast and tested in the laboratory over an effective span of 3,000 mm. Five beams were strengthened with bonded SIMCON and CFRP laminates at the bottom under virgin condition and tested until failure; the remaining two beams were used as control specimens. The static responses of all the beams were evaluated in terms of strength, stiffness, ductility ratio, energy absorption capacity factor, compositeness between laminate and concrete, and the associated failure modes. The theoretical moment-curvature relationship for the test specimen and the load-displacement response of the strengthened beams and control beam were predicted using FEA software ANSYS. A comparison was made between the numerical (ANSYS) with the experimental and theoretical results. The results showed that the strengthened beams exhibit increased flexural strength, enhanced flexural stiffness and composite action until failure.

The cost of civil infrastructure constitutes a major portion of the national wealth. The rapid deterioration of Reinforced Concrete (RC) structures has thus created an urgent need for the development of novel, long-lasting and cost-effective methods for repair, retrofit and new construction. As the number of civil infrastructure systems increases worldwide, the number of deteriorated buildings and structures also increases. Complete replacement is likely to be an increasing financial burden and might certainly be a waste of natural resources if upgrading or strengthening is a viable alternative (Hollaway and Leeming, 1999).

A promising new way of resolving this problem is to selectively use advanced composites such as High-Performance Fiber Reinforced Cementitious Composites (HPFRCCs). With such materials novel repair, retrofit and new construction approaches can be developed and that would lead to substantially higher strengths, seismic resistance, ductility, corrosion resistance and durability, while also being faster and more cost-effective to construct than conventional methods (Ziad and Jack, 1997). In the present days, life extension of structures through strengthening is becoming an essential activity. A host of strengthening systems have been devised and adopted over the years. The choice of the strengthening system depends on the specific performance requirements. Plate bonding technique has gained widespread acceptance as a potential solution. Reinforcing concrete with steel greatly increases its usefulness as building material. Although rebar and wire mesh provide the bulk of this reinforcement, steel fiber has gained an increasing share in the market. One promising new development uses steel fiber mats (Figure 1) to reinforce the concrete matrix. The new approach called SIMCON produces concrete components with extremely high flexural strength (Lloyd et al., 1992). Since SIMCON is manufactured using pre-made continuous fiber mats, delivered in large rolls, fiber placement is substantially simplified.

Structural Engineering Journal, Reinforced Concrete Beams, Slurry Infiltrated Mat CONcrete, Carbon Fiber Reinforced Polymer, Reinforced Concrete Structures, Civil Infrastructure Systems, Conventional Methods, Laboratory Experiments, Civil Engineering Applications, Steel Elements, Beam Elements.