Pond ash is a mixture of fly ash and bottom ash obtained from thermal power plants. It has pozzolanic properties and is commonly treated with cement to impart cohesion and improve strength. The cement stabilized pond ash is an alternative to conventional materials used in compacted subgrade and subbases in pavements. While the strength gain is addressed by the unconfined compressive strength (UCS) test, the mechanisms and the resulting compounds that are responsible for strength gain is not fully understood. In this study, an attempt is made to understand the interaction mechanisms between cement and pond ash by quantifying the influence of the dosage of cement, curing period, and curing temperature using FTIR spectroscopy. In the cemented pond ash, the hydration products formed in cement triggered pozzolanic reactions with silica present in pond ash to form C-S-H, which is responsible for increased strength gain. The C-S-H formation did not vary linearly with cement content/ curing period/ curing temperature due to the pozzolanic reactions and the magnitude of influence exerted by each of these parameters depended on the other two parameters.
Resilient modulus and permanent deformations are two important parameters required for the design of pavements. The effects of cement content, compaction energy and moisture content on these parameters are studied. The UCS strength and deviator stress at failure from static triaxial tests increased with the dosage of cement and compaction energy. The increase in cement content is found to induce cohesion, whereas the increase in compaction energy increased the angle of internal friction, and both lead to an increase in shear strength. The influence of water content is less significant, as the pond ash is inert material devoid of clay. A criterion is proposed for establishing shakedown ranges based on permanent strain variation with the number of cycles. The resilient modulus and permanent strains are fitted with various available models, and the parameters for the best fit model are determined.