Effect of Curing Temperature on the Compressive Strength of Sand, Fly Ash, and Lime Blends
Silvani Carina1; Nilo Cesar Consoli1; Guilherme Borges Masuero1; Eduardo Braun1
1 UFRGS
Resumo
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 the first rational dosage methodology for soil-fly ash-lime was developed by Consoli et al. (2011a) considering the porosity/lime ratio (η/Liv), defined by the porosity of the compacted mixture divided by the volumetric lime content, as an appropriate parameter to evaluate the unconfined compressive strength (qu) of soil-fly ash-lime mixtures. On the other hand, even though it is already recognized by previous studies (e.g., Rojas and Cabrera 2001, 2002; Consoli et al. 2001; Al-Mukhtar et al. 2010a, b) that strength of soil-fly ash-lime mixes (based on pozzolanic reactions) is dependent on temperature (T), which acts as a catalyzer of pozzolanic reactions, it is still unknown if the effect of curing temperature can be inserted in a rational methodology. So 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 unconfined compressive strength (qu) of sand-fly ash-lime blends. A series of unconfined compression tests were carried out in 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/m³ to 16kN/m³, curing temperature 20º, 35º and 50ºC, time curing period of 28 days and fly ash content of 25%. The results show that increasing curing temperature in the blend, for the whole range of lime studied, increases qu. A power function fits well as the relation between qu with η, and a linear function fits well the relation between qu with L 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 qu of the studied blends for the whole range of lime, porosities and tem
Palavras-chave: Lime; Fly ash; Sand; curing temperature; lime stabilization