Highway Research Record

II. PAVEMENT ENGINEERING AND PAVING MATERIALS
1. SOIL STABILISATION, LOW GRADE MATERIALS AND LOW VOLUME ROADS
COMPLETED PROJECTS
Soil Stabilization for Pavement Sub Base Construction

Duration: April 2003 to September 2004
Larsen and Toubro Limited, ECC Division, Chennai. (R, S, I)

Scope and Objectives

The objective of the study is to improve the soil CBR

Methodology
(i) Trials conducted using different types of stabilizers such as,
a. Lime
b. Fly ash
c. Fly ash with sand
d. Fly ash with lime
e. Bio enzymes
f. Chemical agents

(ii) Following different percentage of stabilizers by weight of soil were used in trials;
a. Lime - 1 to 3%
b. Fly ash - 10 to 50%
c. Fly ash with sand - 10 to 30%
d. Fly ash with Lime - 6 to 28%
e. Bio enzymes – Dosage as recommended by supplier
f. Chemical agents – Dosage as recommended by supplier

(iii) To see the effect of stabilizers on soils conventional test were carried out as per SP: 36 (Part – I).

Conclusions
(i) The optimum dosage of lime addition, of 3% increases the CBR value of clayey soils from 1 to 46%.
(ii) Marginal increase in CBR value is 1.5% by the addition of 20% of fly ash.
(iii) Marginal increase in CBR value is 2.5% by the addition of 30% of fly ash with sand combination.
(iv) Marginal increase in CBR value is 6.3% by the addition of 28% of fly ash with lime combination.
(v) Bio enzymes show no significant improvement on CBR value of clayey soil.
(vi) In clayey soils chemical agents show significant improvement on CBR value from 1.7% to 26%.