Towards innovative design and construction standards for lime stabilised subgrades

Abstract

Recycling of existing and virgin pavement materials has been carried out successfully in Malaysia since the 1980's using the process of Insitu Stabilisation. The majority of specified works have been completed using General Purpose cement as the binding agent for use in granular base and sub base materials. The use of lime is becoming more popular in Malaysia as asset owners realise the importance of creating sound platforms to build upon with pavement structures. In pavement design, the two most critical inputs that influence the overall thickness of a pavement structure are the traffic loadings and the design subgrade CBR. Subgrade stiffness is the controlling variable that can be designed for improvement and should be enhanced wherever possible. Lime is particularly suited to dramatically improve the bearing capacity, reduce the volumetric instability and decrease the moisture susceptibility of clayey, expansive and plastic materials which are commonly encountered in pavement subgrades. Due to a current lack of design methodologies and construction specifications in Malaysia incorporating lime stabilised materials, this paper will explore the influencing factors for design of lime stabilised subgrades with an emphasis on thickness design and mix design parameters.