Behavior of Soil–Fly Ash–Lime Blends under Different Curing Temperatures

Compaction of layers of soil–fly ash–lime blends is often used to improve soil conditions for infrastructure projects. Such understanding is the starting point to develop more rational dosages that allow for a more efficient use of resources. To achieve this objective the present research aims to quantify the influence of curing temperature (T), amount of lime (L), porosity (η), and porosity/lime ratio (η/Liv) on the assessment of splitting tensile strength (qt) and unconfined compressive strength (qu) of sand–coal fly ash–lime blends. A series of splitting tensile and unconfined compression tests were carried out in the present work. The results show a linear function fits well the relation between qt and qu with L, and a power function fits well as the relation between qt and qu with η for all curing temperatures of the specimens. It was also shown that the porosity/lime ratio (η/Liv) is a good parameter in the evaluation of qt and qu of the studied blends for the whole range of lime, porosities and temperature studied, at specific amount of coal fly ash (25%) and curing time period (28 days). The volumetric cementitious material content (Liv) is adjusted by an exponent (0.30 for all curing temperatures blends) to end in unique correlations for each temperature. For the sand, coal fly ash, lime, curing time period and curing temperatures, a unique relationship was achieved linking qt as well qu to η; Liv and T. For a given curing time period (28 days), the relations qt-η/Liv and qu-η/Liv versus T are shown to vary linearly up to a threshold, when asymptotes occur. Finally, the relation between qt/qu is a constant and equal to 0.19 for the whole range of L, η and T studied.