Dynamic Behaviour of Pond Ash Mixed with Coir and Crumb Rubber

Abstract

An experimental program was conducted to determine the dynamic properties of pond ash (PA) and pond ash mixed with admixtures like crumb rubber (CR) and coir fiber (CF) which are wastes of different industries. Additives CR and CF were mixed separately with pond ash in a percentage ranging from 0%-20% at an interval of 5% and 0%-2% at an interval of 0.5% by weight of pond ash, respectively. Dynamic properties (Shear modulus, Number of cycles to initiate liquefaction, Degradation index and Damping ratio) for pond ash mixes were determined using strain-controlled cyclic tri-axial apparatus. The shear strain was kept constant at 1.2% and the frequency varied from 0.4 to 1 Hz. Liquefaction resistance improves when crumb rubber is added to pond ash, however adding Coir fiber to pond ash has essentially no effect on the number of cycles required to initiate liquefaction. The dynamic shear modulus decreases when crumb rubber was mixed in pond ash whereas when coir fiber is added to pond ash, the dynamic shear modulus increases significantly. A mix of PA, CR, and CF was also tried to balance the number of cycles required to initiate liquefaction and shear modulus. The mixed sample in the proportion of PA (84%) + CR (15) + CF (1%) can be termed a balanced mix as the number of cycles to initiate liquefaction was more than all PA-CF mixes and also the shear modulus was more than all PA-CR mixes. Damping ratio increases with increasing frequency of loading (0.4 to 1 Hz).