Comparison between cement and fly ash geopolymer for stabilized marginal lateritic soil as road material

ABSTRACT

The stabilisation of marginal lateritic soil using cement and fly ash (FA) geopolymer with a liquid alkaline activator was investigated. In this study, soil with satisfactory gradation and percentage of wear was selected. Only the soaked California Bearing Ratio (CBR) value must be enhanced to satisfy the requirement to form a suitable pavement subbase material. Field CBR tests were conducted for both geopolymer- and cement-stabilised soils used as pavement subbase materials. The soaked CBR of cement- and FA-geopolymer-stabilised marginal lateritic soil of various mixing percentages at 14 days satisfied the standard requirements specified by the government agencies in Thailand. Equations were established from field test data to predict the CBR at any testing time. The CBR development of cement-stabilised soil took more time than that of geopolymer-stabilised soil. The appropriate mixing percentages of cement and FA geopolymer with marginal lateritic soil were 3–5 and 4–8%, respectively. Microstructural analysis indicated that the stabilised soil exhibited a denser structure, which corresponded to the CBR increment. The findings of this study will enable the implementation of cement and FA geopolymer as successful stabilisers for pavement subbase materials.

KEYWORDS:

• Geopolymer
• lateritic soil
• subbase material
• field CBR
• Portland cement

Acknowledgement

The authors would like to acknowledge the financial support provided by King Mongkut’s University of Technology North Bangkok under the contract No. KMUTNB-GOV-55-16.

Additional information

Funding

This work was supported by the King Mongkut’s University of Technology North Bangkok [contract number KMUTNB-GOV-55-16].