Towards Developing Paving Materials Acceptance Specifications for Lateritic and Saprolitic Soils

摘要

The principle of ideal grading, low plasticity and higher compactive effort producing higher density and higher bearing strength of the compacted material for satisfactory pavement performance has characterized pavement materials acceptance specification requirements and practices related to the temperate zone countries. Investigations of cases of premature distress and deteriorations of pavements in some tropical environments have revealed that in addition to selecting well-graded gravels and aggregates to produce high compaction densities and bearing strengths for design, serious attention should also be given to the influence of the nature, geo-chemical, chemical and mineralogical compositions of the materials, testing and geomechanical rating procedures, construction techniques, as well as pavement maintenance history and environmental conditions. For tropically weathered materials formed in diverse climatic and drainage conditions, there is the need for materials oriented approach that integrates relevant aspects of such fields as engineering geology, geomorphology, geochemistry, petrography, pedology, climatology, rock and soil mechanics, innovative roadway design and construction methods as well as cost-effective roadway management and maintenance strategies, etc. A key component of this approach would be the construction and instrumentation of road test sections in relevant climatic, geologic, soils and drainage conditions for long-term serviceability and structural integrity assessment and evaluation. The objective of this lecture is to highlight the key factors, characteristics and parameters useful for developing materials oriented paving materials acceptance specifications for lateritic and saprolitic soils.