Durability of Soil–Cements against Fatigue Fracture

Abstract

Cementitious stabilization is a common method of ground improvement when weak foundation soils are encountered in practice, and marginal or nonstandard materials such as recycled aggregates are used in civil engineering construction. Long-term durability of stabilized materials becomes an issue, especially when it involves one or more recycled materials with unknown and often questionable properties. The study presented herein investigates the fatigue durability, endurance limit, and damage accumulation process in recycled crushed concrete aggregate stabilized with cement–fly ash mixtures. Results show that the $2\text{million}\text{cycles}$ fatigue endurance limit for the stabilized recycled aggregate was nearly 53% of the static modulus of rupture, indicating that the fatigue strength of this material is quite similar to or better than other traditional cementitious composites. It was also found that the accumulated permanent deformation and the expended fatigue life can be related by a nonlinear power law, and the fatigue damage in this material approximately follows Miner’s rule for cumulative damage. Finally, the importance of developing innovative testing methods for durability assessment are highlighted, which include coupled mechanical and environmental loadings to simulate the most damaging field conditions, and accelerated aging and life prediction processes using the Arrhenius time–temperature superposition methods.