Shear Strength of Self-compacting Concrete Containing Different Fillers and Coarse Aggregates

An experimental investigation was conducted to evaluate the shear strength provided by different self-compacting concrete mixes proportioned using different fillers and coarse aggregates. A total of 28 simple beams without web reinforcement were tested in flexure. The test parameters included the use of gravel versus crushed dolomite as coarse aggregates, the amount of longitudinal reinforcement and the composition and percentage of fillers. Dolomite stone powder with either silica fume or fly ash were used as fillers replacing cement aiming at reducing the cost of the mix and obtaining better performance. The test results indicated that the overall structural performance in terms of cracking pattern and shear strength was comparable in all mixes. The potentials of developing shear strength and post cracking shear resistance were better when gravel was used as coarse aggregate and when relatively high fractions of dolomite powder were used as cement replacement

Behaviour of Fiber Reinforced Concrete Beams with Spliced Tension Steel Reinforcement

The aim of the current work is to describe the flexural and bond behaviour of simply supported concrete beams with tension reinforcement spliced at mid-span. The parameters included in the study were the type of the concrete, the splice length and the configuration of the hooked splice. Fifteen beams were cast using an ordinary concrete mix and two fiber reinforced concrete mixes incorporating steel and polypropylene fibers. Each concrete mix was used to cast five beams with continuous, spliced and hooked spliced tension steel bars. A test beam was reinforced on the tension side with two 12-mm bars with a splice length of 20 and 40 times the bar diameter. The hooked bars were spliced along 20 times the bar diameter and provided with 45-degree and 90-degree hooks. The test results in terms of cracking and ultimate loads, cracking patterns, ductility, and failure modes are reported. The results demonstrated the consequences due to short splices and the improvement in the structural behaviour due to the use of hooks and the confinement provided by the steel and polypropylene fibers

Experimental Evaluation of Steel–Concrete bond Strength in Low-cost Self-compacting Concrete

The main objective of this research was to evaluate the potentials of self-compacting concrete (SCC) mixes to develop bond strength. The investigated mixes incorporated relatively high contents of dolomite powder replacing Portland cement. Either silica fume or fly ash was used along with the dolomite powder in some mixes. Seven mixes were proportioned and cast without vibration in long beams with 10 mm and 16 mm steel dowels fixed vertically along the concrete flow path. The beams were then broken into discrete test specimens. A push-out configuration was adopted for conducting the bond test. The variation of the bond strength along the flowing path for the different mixes was evaluated. The steel-concrete bond adequacy was evaluated based on normalized bond strength. The results showed that the bond strength was reduced due to Portland cement replacement with dolomite powder. The addition of either silica fume or fly ash positively hindered further degradation as the dolomite powder content increased. However, all SCC mixes containing up to 30% dolomite powder still yielded bond strengths that were adequate for design purpose. The test results demonstrated inconsistent normalized bond strength in the case of the larger bar diameter compared to the smaller one