Syed Aamir’s scientific contributions

In this study, the effect of bentonite and silica fume (SF) on the mechanical properties of concrete reinforced with micro polypropylene fibers (PPF) has been evaluated. The mixes are catagorized as one control mix, two binary mixes (i.e. 20% SF/ 20% bentonite), one ternary mix (i.e. 20% SF and 20% bentonite) also known as ternary control mix (TCC) , and five additional ternary mix strengthened with different dosages (0.25%, 0.50%, 0.75%, 1% and 1.25% by vol.) of polypropylene fibers (PPF). Microstructural analysis of concrete specimens was performed to identify changes in hydration products by using scanning electron microscopy (SEM). Experimental results show that the additional ternary mix containing 0.5% polypropylene fibers as an optimum dosage showed an increase in compressive strength up to 24.9% and 45% at 28 and 90 days as compared with control mixes at respective ages respectively. Mixing of small dosages of fibers (0.25-0.75%) with TCC can enhance flexural strength of concrete up to 12-18% due to strengthening of PPF against the propagation of flexural cracks. The addition of 20% bentonite in the binary mix creates denser microstructure and refine internal pores of the concrete.

This paper reports the mechanical & durability properties of bentonite & silica fume (SF) concrete containing fibrillated micro polypropylene fibers (PPF). The fresh property was investigated by slump test & mechanical property was investigated by compressive strength & ultrasonic pulse velocity (UPV) tests. For durability properties, permeability test was performed. This research is based on the previous published research & selected the optimum percentages of supplementary cementing material (SCMs) for bentonite & SF. The concrete mixture consists of total of nine mixes: control mix (CC), two binary mixes (i.e., 10% bentonite (B10SF0P0), 10% SF(B0SF10P0)), ternary mix (B10SF10P0), also known as ternary control mix (TCC) & then additional mixes by adding polypropylene fiber equal to 0%, 0.25%, 0.50%, 0.75%, 1% & 1.25% in TCC. It was concluded that all the binary and ternary mixes showed decrease in the workability. The UPV test indicated good quality of concrete for binary mixes and ternary mixes up to the PPF content equal to 0.75%. It was observed that compressive strength & permeability properties of concrete were improved for both the binary mixes and ternary mixes up to addition of PPF equal to 0.5%. PPF increased the deformability properties & completely changed the failure pattern of concrete as compared to ternary mix without PPF.