Abstract

This study investigated the influence of beam depth with varying longitudinal reinforcement without shear reinforcement. Size effect, which is described here in as the decrease in shear strength with the increase in the depth of members, is not evaluated sufficiently enough. To this end, fifteen palm kernel shell (PKS) reinforced concrete beams varying from 150 to 300 mm were tested to investigate their size effects on ultimate shear capacity and failure modes. Test variables were longitudinal reinforcement ratio (ρw varying from 1 to 2%) and effective depth of beams (varying from 120 to 265 mm) with average compressive strength (fcu) = 30.3 MPa and shear span to effective depth (av/d) = 2.5. For the range of variables tested, the test results were compared with the strengths predicted by the ACI 318-08 and BS 8110 with and without reduction factors. All tested beams failed in shear failure modes and were influenced by the beam depth and amount of longitudinal reinforcement. The PKS beams were found to develop sufficient strength after diagonal cracking to continuously transfer loads until failure.

Key words: Palm kernel shell concrete, size effects, longitudinal reinforcement, shear strength, ACI 318-08, BS8110.