Browsing by Author "Bagampadde, U."

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    Influence of aggregate chemical and mineralogical composition on stripping in bituminous mixtures
    (International Journal of Pavement Engineering, 2005) Bagampadde, U.; Isacsson, U.; Kiggundu, B. M.
    The influence of aggregate chemical and mineralogical composition on moisture sensitivity was investigated using 11 aggregates from typical tropical and temperate climates and one bitumen. Mix design and compaction were based on Swedish Road 94 hot mix base specifications and moisture damage was determined using resilient modulus and tensile strength ratios. As much as practically possible, air voids, gradation, compaction level, bitumen content and curing were controlled. Mixtures from aggregates containing sodium and potassium exhibited relatively high moisture sensitivity. The converse was apparent for aggregates with calcium, magnesium and iron. No significant correlation was observed between the strength ratios and contents of Al2O3 and SiO2. Stripping was generally high for aggregates with quartz and alkali feldspars, although one aggregate with practically 100% quartz showed low moisture sensitivity. Statistical analysis showed good correlation between resilient modulus and tensile strength ratios.
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    The use of locally available sand in stabilization of Ugandan clayey soils: Case study of clayey soil from Busega area
    (Umaru., 2011) Jjuuko, S.; Kalumba, D.; Bagampadde, U.
    Clayey soils need to be stabilized to improve their engineering properties and make them suitable for pavements and foundation engineering. Stabilization of pavements and foundation engineering soils in Uganda has traditionally relied on treatment with lime and cement and most designers (engineers) are hesitant to specify nontraditional stabilizers, like sand, without evidence of material effectiveness. This study aimed to use sand to improve the engineering properties of a typical Ugandan clayey soil. Sand was specifically selected because of its abundance locally. A series of laboratory experiments were implemented for specimens whose sand contents ranged between 20 - 80%. The results confirmed that sand blending diminishes shrinkage behavior of clayey soils. Additionally, plasticity index and shrinking potential decreases from 30.5% to non-plastic and from 9.3% to 1.8% respectively depending on the sand concentration in the composite. The MDD and OMC increased from 1867 to 2357 kg/m3 and decreased from 16.5 to 8.5%, respectively, at sand blends of 20-100% while the unconfined compressive strength decreased from 787 to 95kPa at sand blends of 20-60%. The soil internal friction angle concerning shear strength parameters was enhanced from 26.6 to 42.1o and soil cohesion decreased as well from 62 to 2kN/m2 at sand blends of 20-80%. At sand blends 20- 80%, consolidation settlement was lowered from 2.00 to 1.52