Nasir Shafiq

strengthening of reinforced concrete (RC) beam using Fibre Reinforced Polymer (FRP) revealed as the most efficient material due to its various mechanical properties. The previous experimental studies conducted to discuss strengthening schemes for RC beam, based on the observed crack pattern and failure mechanism for strengthening RC beam. The development of crack formation on RC beams under loading identifies the mode of failure and strengthening scheme required, such as to increase the flexural capacity of RC beam; FRP is applied at the tension zone. Similarly, for shear and torsion strengthening FRP wraps are being applied at the faces of the beam. The studies have shown the high strength in shear and torsion is achieved by applying U-shape wrap. Full warp gives high strength in torsion strengthening but practically the application of full wrap on RC beam is impossible and required more in-depth study to propose practical solutions. However, the combined effects of flexure, shear and torsion have not been discussed yet. Therefore, the strengthening schemes from literature are combined to propose new strengthening scheme for RC beam under combine the action of flexure, shear and torsion. However, experimental data are required to validate the proposed scheme.

ABSTRACT RC beams as a structural member contain a variety of non-uniform loads. These non-uniform loads caused combined effects of flexure and torsion. There are numerous studies available, that suggests different strengthening schemes using FRP laminates, as a solution for flexure and torsion deficient beams. Most of the experimental studies suggested individual strengthening schemes for flexure or torsional deficiency RC beams. However, the combined effects were not studied due to difference in experimental setup, testing procedure and specimen detailing. Therefore, the outcome of previous studies was needed to combine together to facilitate the strengthening process as a guideline case of such deficiency. Therefore, a combined review is presented by suggesting different configuration for flexure and torsion deficient RC beams. Most of the studies suggested that the application of FRP laminates at the soffit of beam is suitable for flexural strengthening. The application of U-shape or full wrap are suitable for strengthen torsion deficient beams. Similarly, 45° wraps are more effective than 90°wraps for improving ductility of torsion deficient beams.

ABSTRACT Eccentric loads are very common in structures due to building configuration. Unequal slab length, circular ramp, large cantilevers are very common in modern architecture. The RC beams in previous studies were tested under the three and four point uniform loads. Therefore, a simple testing setup was arranged to understand the behaviour of RC beam under eccentric load applied at mid span. In this study the single point load applied eccentrically on RC beam. The beams were tested at different eccentricity and compared with control beam tested under the uniform load or zero eccentricity. Results have shown a drastically reduced crack load up to 54% compared to control beam as the eccentricity increased. However, small changed in ultimate load carrying capacity was observed up to 60mm eccentricity. Eccentric load caused biaxial bending due to high concentration of load on one side of beam, which change failure mode of RC beam from ductile to brittle.

ABSTRACT CFRP strengthened reinforced concrete (RC) beams are usually tested under either three points or four point concentric loads; the effect of eccentricity is neglected in many studies. In this experimental program eight RC beams tested in two groups, GROUP ‘A’ & ‘B’. In group ‘A’ four RC beam tested, one control beam tested under concentric load and three under the eccentricity of 40, 60 and 80 mm respectively. The remaining four RC beams in group ’B’ strengthened using carbon fibre reinforced polymer (CFRP) strip and tested under the 60mm eccentricity. The experiment has confirmed the behaviour transformation from flexure failure to local failure due to variation in eccentricity. Therefore, the effects of eccentricity cannot be neglected and required special consideration before applying strengthening scheme on RC beam. The RC beams strengthen using CFRP have the ability to enhanced the load carrying capacity of beams tremendously, but the eccentric load effect on ductility, and failure mode of RC beams.

ABSTRACT Rice is a primary source of food for billions of people and covers 1% of the earth’s surface. On average 20% of the rice paddy is husk, giving an annual total production of 120 million tones. Nowadays, there are two common methods used to dispose the rice husk which is either it is being dump or burnt. Rice husk ash (RHA) which is produced by burning paddy husk led to the issue of ozone layer depletion. It also causes damage to the land and the surrounding area where it is being dumped. Previous studies have pointed out that RHA produced contains more than 80% pure silica and if properly prepared, it is in an active form which behaves very much like cement. Same goes with used engine oil (UEO). Many people are aware that UEO shouldn’t be dumped, but recycled. It is incredibly toxic stuff and a gallon can contaminate one million gallons of water. Pouring it on land doesn’t reduce the risk either as it can seep down into the water table.The objective of this research is to obtain an optimum percentage of inclusion of microwave incinerated rice husk ash (MIRHA) as a cement replacement and UEO in order to produce a better concrete in terms of compressive strength compared to normal OPC concrete. The test results showed MIRHA concrete performed better than normal OPC concrete and the incorporation of UEO and MIRHA in concrete showed the compressive strength give better performance.

... Properties of self-compacting concrete containing class F fly ash. Materials and Design 32(3): 1501-1507 CrossRef. Thakur RN, Ghosh S. 2006. Effect of mix composition on compressive strength and microstructure of fly ash based geopolymer composites. ...