Use of soft limestone for road-base construction in Belize.


The results of a highway experiment, constructed in May 1978 in northern

Belize, designed to investigate the suitability of locally occurring calcareous

materials, known as marls, for road bases arc discussed. The

marls comprise high-purity carbonate materials containing mainly silt-sized

particles and fall outside the grading, plasticity, and strength specifications

normally required for road bases. Three marls, each with

slightly different characteristics, were substituted as road base for

crushed stone. One of the marls was also stabilized with ordinary Portland

cement. Detailed monitoring was then undertaken periodically to

determine their performance. The road pavement was constructed on an

embankment to ensure good drainage. A good quality surface dressing

seal has been maintained. After 19 years of traffic, measured at 1.3 million

equivalent standard axles, the marl road bases have performed at

least as well as the crushed stone. The cement-stabilized marl road base

performed exceptionally well. Stabilization would enable the use of more

plastic marls.


Seventh International Conference on Low-Volume Roads, Baton Rouge, Louisiana, USA, 23-26 May 1999. TRL - Crowthorne, UK. pp. 13

Use of soft limestone for road-base construction in Belize.

Published 1 January 1999