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Jomo Kenyatta University of Agriculture and Technology (2005)

Study of calcrete as a road construction material in arid region of Northern Kenya

Godana, Abubakar Hargura

Titre : Study of calcrete as a road construction material in arid region of Northern Kenya

Auteur : Godana, Abubakar Hargura

Université de soutenance  : Jomo Kenyatta University of Agriculture and Technology, Kenya

Grade : Master of Science (MS) 2005

Résumé
This research study was on calcrete as a road construction material for low volume sealed roads in the arid region of Northern Kenya. The main objective of the study was to establish the properties of calcrete materials that relate to their suitability as road construction material. Materials from six sites were subjected to carbonate content test so as to establish if the materials are actually calcrete and the two materials with the highest carbonate content selected for further testing. The materials from the two sites were subjected to soil index tests, heavy proctor and vibrating hammer compaction tests and California Bearing Ratio (CBR) tests at different moisture contents under soaked and unsoaked condition so as to establish the properties of the materials and effect of moisture on their strength. Material moulded at 95% Maximum Dry Density (MDD) and optimum moisture content were tested for soaked CBR after being subjected to three different conditions of four days of wetting and drying, curing only and drying only. The materials were mixed with sand at proportions determined after compaction and subjected to all the above tests. The results obtained indicated that plasticity index results were erratic while linear shrinkage results were consistent. The CBR value increased by between 100% and 200010 between optimum moisture content and dry end moisture content. Addition of sand resulted in lower but erratic plasticity index and consistent linear shrinkage and increased compacted strength, which is still moisture susceptible. The study concludes that in the case of calcrete materials, the material properties that relate to their suitability as a road construction material in the arid region are linear shrinkage, and CBR at the likely in-service moisture content. Calcretes undergo self-stabilisation and the best method for testing is wetting and drying cycles. ElRage calcrete is suitable for dry compaction.

Mots clés : Roads and highways / Highway construction

Présentation (Research Kenya)

Page publiée le 22 septembre 2010, mise à jour le 6 mars 2018