Study on flexural strength, modulus, and fatigue cracking of cementitiously stabilised materials

Flexural and resilient properties (flexural strength, flexural modulus, fatigue cracking, and resilient modulus) of common cementitiously stabilised materials (CSMs) in pavement systems are presented in this paper. These properties are critical parameters for pavement analysis to determine stress/strain and thus, pavement performance prediction. Four materials (sand, gravel, silt, and clay) and four binders (cement, lime, class C fly ash, and a combination of lime and class F fly ash) were studied. Beam and cylindrical specimens were prepared to study the flexural and resilient properties, respectively. The effect of compaction, binder content, and curing time was evaluated. Modulus growth tests were conducted at 28, 56, 90, 120, 150, and 180 d. A power relationship (R2 = 0.92) between flexural strength and unconfined compressive strength (UCS) for the CSMs was observed. The flexural strength test adopted here was found to be applicable for the whole range of CSMs – both heavily and lightly stabilised soils. The results indicate that determination of flexural modulus is strongest at a stress level of 30%. The number of cycles to achieve a 50% reduction from initial modulus could be considered to define fatigue failure if the specimen does not fail within 8 h.