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Utilization of reclaimed asphalt pavement (RAP) in road construction has become a common practice worldwide. This is in-line with the global objective of sustainable development aimed at lowering the consumption of dwindling sources of virgin aggregates and coming up with viable solutions to deal with RAP materials generated from highway rehabilitation projects. In the present study, an investigation of the laboratory performance of foamed bitumen stabilized material mixes for use in base courses was conducted. A suitable laboratory mix design was developed to evaluate the effect of different proportions of bitumen and Portland cement on properties of cold RAP materials. Cement content was varied at percentages of 0.5, 0.75, and 1.0% while bitumen content was varied at percentages of 1.75, 2.0, and 2.5%. Also, mixes utilizing typical bituminous surfacing materials encountered on paved road networks during road rehabilitation were assessed. RAP materials from pavements comprising thick layers of asphalt concrete and thin layers of surface dressing as well as unbound crushed aggregate made from fresh quarried rock often used for road bases were considered. Optimal values of 1.0% and 2.5% for cement and bitumen contents, respectively, were determined and used to come up with mixes which incorporated different surfacing materials. Mixes developed were analyzed for mechanical properties of indirect tensile strength (soaked and unsoaked), indirect tensile fatigue, elastic modulus and rutting. RAP materials from thin layers of surface dressing were determined as the best performing surfacing material for cold foamed in-place pavement recycling technology.
Rodgers Bangi Mugume. Investigation of Foamed Bitumen Mixes Using Reclaimed Asphalt Pavement Materials for Cold Recycling Technology. International Journal of Pavement Research and Technology 2021, 1 -13.
AMA StyleRodgers Bangi Mugume. Investigation of Foamed Bitumen Mixes Using Reclaimed Asphalt Pavement Materials for Cold Recycling Technology. International Journal of Pavement Research and Technology. 2021; ():1-13.
Chicago/Turabian StyleRodgers Bangi Mugume. 2021. "Investigation of Foamed Bitumen Mixes Using Reclaimed Asphalt Pavement Materials for Cold Recycling Technology." International Journal of Pavement Research and Technology , no. : 1-13.
This paper is aimed at assessing the in-service performance of asphalt pavements in tropical climate under severe conditions. The main defect observed on the asphalt pavement was rutting of the asphaltic surfacing, with top-down cracking being experienced on a few sections and not widespread but rather intermittent. Field and laboratory investigations were conducted as well as a review of design and construction records. The defects observed were confined to the wearing course layer of the surfacing with the other underlying layers performing well. Rutting was a result of heavily loaded trucks that moved at very slow speeds due to steep gradients, hence resulting in severely loaded sections. High temperatures due to the warm tropical environment exacerbated the situation and caused the asphalt to flow, hence resulting in rutting and deformation. Also, low air voids in the asphalt mix which were below the recommended design air voids specification aggravated the situation as well as the air voids after refusal density compaction being below the specified critical minimum of 3% after secondary compaction. Top-down cracking was due to binder age hardening and embrittlement resulting from overheating of bitumen during the construction process coupled with heavy truck axles and high tyre pressures. Defects observed, therefore, resulted from an unstable asphalt mix that was not suitable for severe loading conditions; hence, the asphalt concrete laid was out of specification. The Modified Marshall Mix Design method should be used for severe sites where slow speed or heavier traffic is expected.
Rodgers B. Mugume. Effect of Unstable Mix under Severe Traffic Loading on Performance of Asphalt Pavements in Tropical Climate. Advances in Civil Engineering 2020, 2020, 1 -12.
AMA StyleRodgers B. Mugume. Effect of Unstable Mix under Severe Traffic Loading on Performance of Asphalt Pavements in Tropical Climate. Advances in Civil Engineering. 2020; 2020 ():1-12.
Chicago/Turabian StyleRodgers B. Mugume. 2020. "Effect of Unstable Mix under Severe Traffic Loading on Performance of Asphalt Pavements in Tropical Climate." Advances in Civil Engineering 2020, no. : 1-12.
This paper presents an assessment of the contribution of reactive aggregates on performance of asphalt pavements in service in order to better understand how to mitigate likely asphalt pavement failures resulting thereof. A petrographic and mineralogical analysis was done on rocks that were used in the asphalt mix as well as their mineral composition. Also, a visual condition survey, deflection testing and coring of the asphaltic surfacing for further analysis and testing were conducted to establish the extent of the distresses. Results showed that though aggregates tested were meeting the criteria required of a good quality asphalt concrete in relation to mechanical properties, they did not satisfy the other criteria in relation to their mineralogical composition and adhesion. Aggregates were found to be reactive and contained pyroxenes and feldspar which were responsible for deterioration in form of ‘blows ups’ and indentations observed on the pavement surface. Pyroxenes oxidised when they combined with atmospheric components due to their high iron content to form hydrated iron oxides. Feldspars experienced a hydrolytic reaction when they reacted with water to form clay minerals, potassium ions, and silica in solution. Continued exposure of reactive aggregates through water and air permeating into the open textured and cracked asphalt surface will result into total transformation of the pyroxenes into erodible iron oxides and hydroxides hence leading to further deterioration of the asphalt pavement. It is recommended that engineers consider conducting petrographic and mineralogical analysis when sourcing quarries for production of aggregates to be used in asphalt mixes.
Rodgers Bangi Mugume; Steven Musumba. Contribution of reactive aggregates towards the performance of in-service asphalt pavements. International Journal of Pavement Research and Technology 2020, 14, 530 -536.
AMA StyleRodgers Bangi Mugume, Steven Musumba. Contribution of reactive aggregates towards the performance of in-service asphalt pavements. International Journal of Pavement Research and Technology. 2020; 14 (5):530-536.
Chicago/Turabian StyleRodgers Bangi Mugume; Steven Musumba. 2020. "Contribution of reactive aggregates towards the performance of in-service asphalt pavements." International Journal of Pavement Research and Technology 14, no. 5: 530-536.
This paper is aimed at assessing in-service asphalt pavement cracking in order to fully understand its causes as well as reviewing the possible impact of implementing a new mix design method on failures observed. Field and laboratory investigations were conducted as well as a review of design and construction records. Substitution of a Performance Grade (PG) binder with straight run pen grade binder without performing independent Superpave PG verification tests greatly contributed to cracking. A 20/30 pen grade binder which was utilised had already undergone some change in its properties since its manufacture and therefore did not provide the required workability and crack resistance that it would otherwise have been expected to provide. Target mixing and compaction temperature ranges during construction were higher than those recommended confirming that the binder used had already undergone a change in its physical and chemical characteristics between the time of its manufacture and use. Additionally, a lapse in quality control and assurance during asphalt production and laying resulted in a highly voided wearing course which exacerbated the situation.
Rodgers Mugume; Denis Kakoto. Effect of Inappropriate Binder Grade Selection on Initiation of Asphalt Pavement Cracking. Sustainability 2020, 12, 6099 .
AMA StyleRodgers Mugume, Denis Kakoto. Effect of Inappropriate Binder Grade Selection on Initiation of Asphalt Pavement Cracking. Sustainability. 2020; 12 (15):6099.
Chicago/Turabian StyleRodgers Mugume; Denis Kakoto. 2020. "Effect of Inappropriate Binder Grade Selection on Initiation of Asphalt Pavement Cracking." Sustainability 12, no. 15: 6099.
R.B. Mugume; T. Horiguchi. Prediction of fire spalling in fibre-reinforced high strength concrete. MATEC Web of Conferences 2013, 6, 03002 .
AMA StyleR.B. Mugume, T. Horiguchi. Prediction of fire spalling in fibre-reinforced high strength concrete. MATEC Web of Conferences. 2013; 6 ():03002.
Chicago/Turabian StyleR.B. Mugume; T. Horiguchi. 2013. "Prediction of fire spalling in fibre-reinforced high strength concrete." MATEC Web of Conferences 6, no. : 03002.
Kazuo Watanabe; Mugume Rodgers Bangi; Takashi Horiguchi; Rodgers Mugume. The effect of testing conditions (hot and residual) on fracture toughness of fiber reinforced high-strength concrete subjected to high temperatures. Cement and Concrete Research 2013, 51, 6 -13.
AMA StyleKazuo Watanabe, Mugume Rodgers Bangi, Takashi Horiguchi, Rodgers Mugume. The effect of testing conditions (hot and residual) on fracture toughness of fiber reinforced high-strength concrete subjected to high temperatures. Cement and Concrete Research. 2013; 51 ():6-13.
Chicago/Turabian StyleKazuo Watanabe; Mugume Rodgers Bangi; Takashi Horiguchi; Rodgers Mugume. 2013. "The effect of testing conditions (hot and residual) on fracture toughness of fiber reinforced high-strength concrete subjected to high temperatures." Cement and Concrete Research 51, no. : 6-13.
This experimental study investigates two spalling test methods, for small scale specimens made of fibre-reinforced high strength concrete exposed to elevated temperatures, namely a blowtorch test and a furnace test. The study also aims at developing a relationship between relative maximum pore pressure and spalling, in order to determine a threshold relative maximum pressure for predicting spalling in heated concrete. The test results showed that the blowtorch test was a more effective and economical test method for carrying out spalling tests in small, unloaded and unrestrained specimens. Since such small specimens almost always do not spall during furnace tests, a blowtorch spalling test can help to provide relevant and useful data for mitigation of spalling in real scale structural elements. Also, with a blowtorch spalling test, a clear relationship between relative maximum pore pressures and spalling in heated concrete was observed, and a threshold relative maximum pore pressure above which spalling is likely to occur was suggested.
Rodgers Bangi Mugume; Takashi Horiguchi; Rodgers Mugume. Prediction of spalling in fibre-reinforced high strength concrete at elevated temperatures. Materials and Structures 2013, 47, 591 -604.
AMA StyleRodgers Bangi Mugume, Takashi Horiguchi, Rodgers Mugume. Prediction of spalling in fibre-reinforced high strength concrete at elevated temperatures. Materials and Structures. 2013; 47 (4):591-604.
Chicago/Turabian StyleRodgers Bangi Mugume; Takashi Horiguchi; Rodgers Mugume. 2013. "Prediction of spalling in fibre-reinforced high strength concrete at elevated temperatures." Materials and Structures 47, no. 4: 591-604.
Kazuo Watanabe; Mugume Rodgers Bangi; Takashi Horiguchi; Rodgers Mugume. Effect of Elevated Temperatures on Flexural Behaviour of Hybrid Fibre Reinforced High Strength Concrete. Journal of Structural Fire Engineering 2010, 1, 17 -28.
AMA StyleKazuo Watanabe, Mugume Rodgers Bangi, Takashi Horiguchi, Rodgers Mugume. Effect of Elevated Temperatures on Flexural Behaviour of Hybrid Fibre Reinforced High Strength Concrete. Journal of Structural Fire Engineering. 2010; 1 (1):17-28.
Chicago/Turabian StyleKazuo Watanabe; Mugume Rodgers Bangi; Takashi Horiguchi; Rodgers Mugume. 2010. "Effect of Elevated Temperatures on Flexural Behaviour of Hybrid Fibre Reinforced High Strength Concrete." Journal of Structural Fire Engineering 1, no. 1: 17-28.