Effect of Curing Temperature on Tensile Strength of Sand - Coal Fly Ash - Lime Blends

Soil is the base of most civil engineering constructions, and when it cannot support the construction loads, such problem can be solved through the use of soil stabilization technique. Lime stabilization is a classical technique, but there are still no dosage methods of these mixtures based on more rational criteria. This situation has been changing with researches using the porosity/lime ratio to dose soil-lime. 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) of sand - coal fly ash - lime blends. For this research splitting tensile tests were carried out with cylindrical specimens with diameter and height equal to 50 and 100mm, respectively, with lime contents varying from 3% to 7%, dry unit weight ranging from 14kN/m3to 16kN/m3, curing temperature 20°, 27°, 35° and 50°C, time curing period of 28 days and fly ash content of 25%. The results show the splitting tensile strength increasing linearly with the increase amount of lime and exponentially with the reduction of porosity. It was also shown that the porosity/lime ratio (η/Liv) is a good parameter in the evaluation of qt of the studied blends for the whole range of lime, porosities and temperature studied. 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, moisture content, curing time period and curing temperatures, a unique relationship was achieved linking qtto η, Livand T. For a given curing time period (28 days), the relations qt - η/Livversus T are shown to vary linearly up to a threshold, when become asymptotes.