Characteristics of volcanic ash and natural lime based stabilized clayey soils.(NOTE)

Abstract: Clayey soils are stabilized with various percentages of volcanic ash (VA), finely ground natural lime (NL), Portland cement, and their combinations. The influence of stabilizers and their combinations is evaluated through standard Proctor compaction, unconfined compressive strength, splitting tensile strength, modulus of elasticity, and California bearing ratio (CBR) tests. The durability of stabilized soil mixtures is judged based on drying shrinkage and the influence of water immersion on strength. Correlations between compressive strength, modulus of elasticity, and CBR are also established. Stabilized soil mixtures can be used in various constructions, including road pavements and low-cost housing.

Key words: soil stabilization, volcanic ash, natural lime, mechanical properties, durability.

Resume : Les sols argileux sont stabilises en utilisant differents pourcentages de cendre volcanique, de la chaux naturelle finement broyee, du ciment Portland et diverses combinaisons de ces elements. L'influence des stabilisants et de leurs combinaisons est evaluee en utilisant le test standard de compactage Proctor, la resistance en compression non confinee, la resistance a la traction par fendage, le module d'elasticite et l'essai de portance de Californie (<< CBR >>). La durabilite des melanges de sols stabilises est jugee en se basant sur le retrait de sechage et l'influence de l'immersion dans l'eau sur la resistance. Les correlations entre la resistance a la compression, le module d'elasticite et le << CBR >> sont egalement determinees. Les melanges de sols stabilises peuvent etre utilises entre autres dans divers types de construction incluant les couches de roulement des routes et les habitations a loyer modere. Mots cles : stabilisation des sols, cendre volcanique, chaux naturelle, proprietes mecaniques, durabilite.

[Traduit par la Redaction]

1. Introduction

The natural durability and strength of soil can be improved through the process of "soil stabilization" using different types of stabilizers. Natural oils, plant juices, and animal dung have been used as soil stabilizers for many centuries (Ghavami et al. 1999). Portland cement, hydraulic lime, bitumen, and by-products such as blast furnace slag, fly ash, rice husk ash, and cement kiln dust are also used as stabilizers (Rahman 1986; Chu and Kao 1993; Miller and Azad 2000).

Stabilized soils can be extremely useful construction materials in many countries of the world, especially if they can be produced from locally available resources. Volcanic ash (VA) is found abundantly in volcanic areas, and lime deposits are also available in many parts of the world. The use of natural lime (NL) and VA as stabilizers in soil stabilization can reduce construction costs and can provide an environmentally friendly means of disposal of VA from a volcanic disaster area (Hossain 2000). Limited research had been conducted to investigate the suitability of using VA in soil stabilization in association with cement and NL. This paper presents the results of an investigation on the characteristics of stabilized clayey soils incorporating VA, NL, and cement.

2. Experimental program

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