Browsing by Author "Mwikola, Gabriel Salanga"

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    Correlation of aggregate properties from different test methods
    (University of Dar es Salaam, 1997) Mwikola, Gabriel Salanga
    Existing classification of aggregates for use in highway pavement structures is not precise and several different tests are used in the laboratory to attempt to determine their performance characteristics. This may result in different specifications if the aggregates are from different sources. The aim of this project was to establish few test methods which could be used to classify aggregates for use in highway pavement. Six rock aggregate samples were collected from different operating quarry sources and subjected to engineering tests namely: Specific Gravity and Water Absorption, Aggregate Impact Value, Aggregate Crushing Value, Shape Test, Los Angles Abrasion Value and the Soundness of Aggregate. Generally the samples tested showed high aggregate impact value, aggregate crushing value, specific gravity, low percent loss for aggregate and low water absorption. The characteristics cited above indicate that the rock aggregates can be used for highway pavement work. The classification of aggregates for use in highway pavement structures have been proposed. In the proposed classification it has been found that two tests namely: Aggregate impact test and Soundness test can suffice to test aggregates suitability as highway pavement materials. The Los Angeles abrasion value was selected as the dependent variable because it is more dependable than other abrasion tests as rubbing and pounding action in test simulate the field condition better. Also, correlation of Los Angeles abrasion value with field performance and specifications of the test were established by agencies like AASHTO, Tanzania Highway Standard Specification.3, 12, l0, 14, 15, 16. It is recommended that the proposed classification of aggregates for use in highway pavement be used in the on-going IRP (Integrated Roads Projects) so that specifications can be tried. Such trial will facilitate their refinement with the ultimate goal of having precise test methods.