2 n d International Conference on New Developments in Soil Mechanics and Geotechnical Engineering, 28-30 May 2009, Near East University, Nicosia, North Cyprus Effect of combination of lime and natural pozzolana On the plasticity of soft clayey soils Khélifa Harichane Department of Civil Engineering, Chlef University, Algeria; [email protected] Mohamed Ghrici Department of Civil Engineering, Chlef University, Algeria; [email protected] KEYWORDS: clay, lime, natural pozzolana, plasticity, stabilization ABSTRACT: Clayey soils, especially those with high plasticity index often present difficulties in construction operations because they usually contain expansive clay minerals. However, the engineering properties of expansive clayey soils can be improved by different stabilization techniques. The aim of this paper is to study the effect of using lime, natural pozzolana or a combination of both on plasticity (Atterberg’s limits) of two clayey soils classified as CH and CL according to the unified soil classification system (USCS). The results indicated that for CH class clay soil, plasticity index decreased significantly for samples stabilized with lime and only a slight decrease of plasticity index for samples stabilized with natural pozzolana. On the other hand, for the soil classified as CL class clay, an important decrease of plasticity index was observed for the samples stabilized with natural pozzolana compared to samples stabilized with lime. In addition, the use of lime and its combination with natural pozzolana modifies the clayey soils classification according to the Casagrande plasticity chart. 1 INTRODUCTION During the last decades some limitations have been imposed to constructions; limits on the space occupied and on time for construction; safety and shortage of traditional natural material. Nowadays, it has become difficult to find suitable sites for construction or suitable material sites for earth structures such as highways, dams or runways, within an economic range. In recent years, scientific techniques of soil stabilization have been introduced (Bell 1993; Rogers et al. 1996). Extensive studies have been carried out on the stabilization of soft soils using various additives such as lime and cement (Al Rawas & Goosen 2006). Industrial by-products such as limestone (Okagbue et al. 2000), fly ash (Al Rawas et al. 2005 ; Goswami et al. 2005; Parsons et al. 2005; Kolias et al. 2005), rice husk ash (Al Hassan et al. 2007 ; Muntohar et al. 2000 ; Basha et al. 2003 ; Anisur 1986), silica fume (Bagherpour et al. 2003), cement kiln dust (Miller et al. 2000) have been widely used for soil stabilization. However, limited research had been conducted to investigate the suitability of using natural pozzolana (NP) in soil stabilization. Hossain et al. (2007) used volcanic ash from natural resources of Papua New Guinea for stabilization of soils. Durability tests were conducted for studying the influence of water immersion on strength, water sorptivity and drying shrinkage, but this research work was not focused on studying the plasticity behaviour. Natural pozzolana is found abundantly in extensive areas of Beni-Saf quarry in the West of Algeria (Ghrici et al. 2007). The use of natural pozzolana and its combination with lime in conjunction with soft clayey soils needs to be investigated. As the soil is a good source of alumina, the effects of lime treatment can be enhanced to a great extent if the apparent shortage of silica can 574
Effect of combination of lime and natural pozzolana On the plasticity of soft clayey soils
May 05, 2023
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