Performance of Self Compacting Concrete Containing Fly Ash and MIRHA: Optimum Mix Design and Structural Behavior

Properties of hardened concrete are very important for load resistance, durability,
stability and aesthetic point of view; its properties in fresh state are also very vital for
good workmanship. In view of this, the self compacting concrete simply called SCC was
initiated. The aim of producing of such was that it should be honey-like viscous material
that contain low amount of water and high range water reducers to modify the viscosity of
concrete. The principal aim of this research study was to develop the optimum mix design
of SCC by addressing the issues highlighted in a number of research papers. Investigation
of the rheology of the fresh concrete was made in order to satisfy the criteria of self
compactibility.
Mechanical properties such as compressive strength, modulus of rupture and the
tensile strength were determined. Durability properties that included total porosity,
oxygen and water permeability and the corrosion potential of the selected mixes were
investigated. Structural performance of the selected mixes was determined by conducting
embedded steel bar pull-out test for bond behavior. Reinforced concrete beams were
tested under monotonic loading for flexural/shear capacity with failure mechanism and
dynamic loading for finding the fatigue endurance. A computer simulation using the
software A TENA was performed in order to compare with respect to the static load test
results ofRC beams.
From the investigation of different results it was found that water-to-binder ratio
(w/b) played a vital role in both fresh and hardened states of concrete. By maintaining the
dosage of superplasticizers at optimum level as 3%; w/b can go as low as 0.25 with 10%
fly ash self compacting concrete (FASCC) whereas it can go as low as 0.35 with I 0%
Microwave Incinerated Rice Husk Ash (MIRHA) self compacting concrete. It is worthy
to note that if more than 80 MPa compressive strength of concrete is required at 28-days;
fly ash based SCC will be the optimized solution. If concrete production at 28 days
strength of 60 MPa and below is required, MIRHA SCC (MSCC) blended cement
concrete would be feasible A water-to-binder ratio between 0.25 to 0.37 and a
superplasticizers of 3% were found as the optimum values for producing high
performance SCC that satisfied the criteria of high strength, assurance of durability,