Nathan N Chilukwa | The Copperbelt University (original) (raw)
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Papers by Nathan N Chilukwa
Infrastructures
Rutting is one of the most common distresses in asphalt pavements in Zambia. The problem is parti... more Rutting is one of the most common distresses in asphalt pavements in Zambia. The problem is particularly prevalent at intersections, bus stops, railway crossings, police checkpoints, climbing lanes and other heavily loaded sections, where there is deceleration, slow moving or static loading. The most widely used methods to identify the source of rutting among flexible pavement layers are destructive methods; field trenching and coring methods. The Transverse Profile Analysis method (TPAM), which is a non-destructive method, was suggested by White et al. in 2002 as an alternative method, to avoid the expensive and destructive nature of the traditional methods. In this method, data from the transverse profile of the rutted section is used to deduce the layer of the pavement structure responsible for rutting failure. This study used the TPAM to determine the layers of pavement responsible for rutting on sections of the Chibuluma and Kitwe-Chingola Roads in Zambia. The method was first ...
infrastructures, 2019
Rutting is one of the most common distresses in asphalt pavements in Zambia. The problem is parti... more Rutting is one of the most common distresses in asphalt pavements in Zambia. The problem is particularly prevalent at intersections, bus stops, railway crossings, police checkpoints, climbing lanes and other heavily loaded sections, where there is deceleration, slow moving or static loading. The most widely used methods to identify the source of rutting among flexible pavement layers are destructive methods; field trenching and coring methods. The Transverse Profile Analysis method (TPAM), which is a non-destructive method, was suggested by White et al. in 2002 as an alternative method, to avoid the expensive and destructive nature of the traditional methods. In this method, data from the transverse profile of the rutted section is used to deduce the layer of the pavement structure responsible for rutting failure. This study used the TPAM to determine the layers of pavement responsible for rutting on sections of the Chibuluma and Kitwe-Chingola Roads in Zambia. The method was first validated using the trenching method on the Kitwe-Ndola Road. Results from the TPAM showed good comparability with those from the trenching method. It was established that most of the rutting emanated from the surfacing layer. This is consistent with recent research indicating that most rutting occurs in the upper part of the asphalt surfacing. It was also established that the TPAM was a simpler, faster and less costly method of determining the source of rutting failure compared to the traditional methods.
—Western Province of Zambia is situated in the western parts of the country, neighbouring Namibia... more —Western Province of Zambia is situated in the western parts of the country, neighbouring Namibia, Angola and Botswana. The geology of the area is predominated by sands. Because of this, there is scarcity of good road building materials. Good quality materials have to be hauled over distances in excess of a 100 km. These long haul distances make road construction more expensive in this region compared to other regions in Zambia. It is against this background that a study was conducted to determine whether the abundant sand in the region could be modified/improved such that it can be used for road base and subbase construction particularly for low volume roads. Sands were sampled from three districts in the province namely; Mongu, Senanga and Sesheke. Classification and strength tests were conducted on the sands. The sands were stabilised with varying percentages of Cement and Bitumen. The results of California Bearing Ratio (CBR), Unconfined Compressive Strength (UCS), Indirect Tensile Strength (ITS) and Marshall stability tests showed marked improvements in the properties of the sands after stabilisation.
To adequately design a structure using timber, it is important to know the physical and mechanica... more To adequately design a structure using timber, it is important to know the physical and mechanical properties of the timber. This study was conducted to determine the strength properties for the Pine; one of Zambia's most widely used commercial timber species. Two of the most common species of Zambian Pine were evaluated, viz; Pinus oocarpa and Pinus kesiya. Strength tests conducted included bending and compression parallel and perpendicular to grains. The tests were conducted in accordance with procedures espoused in ASTM D143 and BS 373 standards. Results of the tests showed the bending strengths of Pinus oocarpa averaged about 92.6 MPa while that of Pinus kesiya averaged 77.7 MPa. Compression parallel to the grains varied from 49.4 MPa to 77.6 MPa and 39.9 MPa to 50.5 MPa for Pinus oocarpa and Pinus kesiya respectively while compression perpendicular to the grains varied from 1.4 MPa to 4.0 MPa for Pinus oocarpa and 1.2 MPa to 3.6 MPa for Pinus kesiya. The modulus of elasticity varied from 7,703.7 MPa to 15, 720 MPa for Pinus oocarpa and 7,383.7 MPa to 10,854.4 MPa for Pinus kesiya. The two Pine species were also compared in terms of strength. This was done to aid timber selection. It was found from the tests that the mean bending strength of clear Pinus oocarpa was higher than that of clear Pinus kesiya by almost 19%. The determination of the strength properties of the timbers was done with a view to kick-start the development of a new code of practice for structural use of locally grown timber species in Zambia as the existing standard (ZS 032:1986) has since been withdrawn.
Conference Presentations by Nathan N Chilukwa
Proper record keeping, prioritisation and scheduling of Airport Pavement remedial activities are ... more Proper record keeping, prioritisation and scheduling of Airport Pavement remedial activities are of great importance in facilitating the effective performance of airport infrastructure. Kenneth Kaunda International Airport's current maintenance plan is paper-based and would benefit from the integration of a computerised optimal timing system which would streamline operation, improve record keeping and reform spending in that regard. This study sought to create a server based software application called AeroPave centred on the aforementioned items, suitable for the Kenneth Kaunda International Airport (KKIA) airside pavements in Lusaka, Zambia. The use of different predictive models developed using reliable scientific and engineering methods were considered to accurately plan for future maintenance and funding needs. The selection of the most suitable alternative model was governed by the resources and pavement historical data available. Ultimately a fuzzy-logic prioritisation model was used over analytical hierarchy systems owing to the lack of past standardised condition assessment records required to ensure the latter's reliability. The selected model utilised a Mamdani Inference Engine that accepts two input parameters; the Pavement Condition Index (PCI), the AGE of the Pavement within a 20 year design period and an output parameter; TREATMENT. The output is expressed as a percentage which is related to a treatment class legend that allow users to interpret the results in terms of actual maintenance activities. The AeroPave software was designed to also include a database to store pavement information and work history. A PCI survey was carried out at KKIA with results showing an overall average PCI of 84 for the surveyed areas, namely; the runway, main taxiway and apron. These results were catalogued and added to the systems' database. It can be said from the trends observed from testing of the optimal timing model using sample data derived from the PCI ratings for KKIA that it is possible to use AeroPave at KKIA to recommend the optimal timing for treatment application. Further work needs to done to refine the fuzzy-logic prioritisation to make it more accurate.
Infrastructures
Rutting is one of the most common distresses in asphalt pavements in Zambia. The problem is parti... more Rutting is one of the most common distresses in asphalt pavements in Zambia. The problem is particularly prevalent at intersections, bus stops, railway crossings, police checkpoints, climbing lanes and other heavily loaded sections, where there is deceleration, slow moving or static loading. The most widely used methods to identify the source of rutting among flexible pavement layers are destructive methods; field trenching and coring methods. The Transverse Profile Analysis method (TPAM), which is a non-destructive method, was suggested by White et al. in 2002 as an alternative method, to avoid the expensive and destructive nature of the traditional methods. In this method, data from the transverse profile of the rutted section is used to deduce the layer of the pavement structure responsible for rutting failure. This study used the TPAM to determine the layers of pavement responsible for rutting on sections of the Chibuluma and Kitwe-Chingola Roads in Zambia. The method was first ...
infrastructures, 2019
Rutting is one of the most common distresses in asphalt pavements in Zambia. The problem is parti... more Rutting is one of the most common distresses in asphalt pavements in Zambia. The problem is particularly prevalent at intersections, bus stops, railway crossings, police checkpoints, climbing lanes and other heavily loaded sections, where there is deceleration, slow moving or static loading. The most widely used methods to identify the source of rutting among flexible pavement layers are destructive methods; field trenching and coring methods. The Transverse Profile Analysis method (TPAM), which is a non-destructive method, was suggested by White et al. in 2002 as an alternative method, to avoid the expensive and destructive nature of the traditional methods. In this method, data from the transverse profile of the rutted section is used to deduce the layer of the pavement structure responsible for rutting failure. This study used the TPAM to determine the layers of pavement responsible for rutting on sections of the Chibuluma and Kitwe-Chingola Roads in Zambia. The method was first validated using the trenching method on the Kitwe-Ndola Road. Results from the TPAM showed good comparability with those from the trenching method. It was established that most of the rutting emanated from the surfacing layer. This is consistent with recent research indicating that most rutting occurs in the upper part of the asphalt surfacing. It was also established that the TPAM was a simpler, faster and less costly method of determining the source of rutting failure compared to the traditional methods.
—Western Province of Zambia is situated in the western parts of the country, neighbouring Namibia... more —Western Province of Zambia is situated in the western parts of the country, neighbouring Namibia, Angola and Botswana. The geology of the area is predominated by sands. Because of this, there is scarcity of good road building materials. Good quality materials have to be hauled over distances in excess of a 100 km. These long haul distances make road construction more expensive in this region compared to other regions in Zambia. It is against this background that a study was conducted to determine whether the abundant sand in the region could be modified/improved such that it can be used for road base and subbase construction particularly for low volume roads. Sands were sampled from three districts in the province namely; Mongu, Senanga and Sesheke. Classification and strength tests were conducted on the sands. The sands were stabilised with varying percentages of Cement and Bitumen. The results of California Bearing Ratio (CBR), Unconfined Compressive Strength (UCS), Indirect Tensile Strength (ITS) and Marshall stability tests showed marked improvements in the properties of the sands after stabilisation.
To adequately design a structure using timber, it is important to know the physical and mechanica... more To adequately design a structure using timber, it is important to know the physical and mechanical properties of the timber. This study was conducted to determine the strength properties for the Pine; one of Zambia's most widely used commercial timber species. Two of the most common species of Zambian Pine were evaluated, viz; Pinus oocarpa and Pinus kesiya. Strength tests conducted included bending and compression parallel and perpendicular to grains. The tests were conducted in accordance with procedures espoused in ASTM D143 and BS 373 standards. Results of the tests showed the bending strengths of Pinus oocarpa averaged about 92.6 MPa while that of Pinus kesiya averaged 77.7 MPa. Compression parallel to the grains varied from 49.4 MPa to 77.6 MPa and 39.9 MPa to 50.5 MPa for Pinus oocarpa and Pinus kesiya respectively while compression perpendicular to the grains varied from 1.4 MPa to 4.0 MPa for Pinus oocarpa and 1.2 MPa to 3.6 MPa for Pinus kesiya. The modulus of elasticity varied from 7,703.7 MPa to 15, 720 MPa for Pinus oocarpa and 7,383.7 MPa to 10,854.4 MPa for Pinus kesiya. The two Pine species were also compared in terms of strength. This was done to aid timber selection. It was found from the tests that the mean bending strength of clear Pinus oocarpa was higher than that of clear Pinus kesiya by almost 19%. The determination of the strength properties of the timbers was done with a view to kick-start the development of a new code of practice for structural use of locally grown timber species in Zambia as the existing standard (ZS 032:1986) has since been withdrawn.
Proper record keeping, prioritisation and scheduling of Airport Pavement remedial activities are ... more Proper record keeping, prioritisation and scheduling of Airport Pavement remedial activities are of great importance in facilitating the effective performance of airport infrastructure. Kenneth Kaunda International Airport's current maintenance plan is paper-based and would benefit from the integration of a computerised optimal timing system which would streamline operation, improve record keeping and reform spending in that regard. This study sought to create a server based software application called AeroPave centred on the aforementioned items, suitable for the Kenneth Kaunda International Airport (KKIA) airside pavements in Lusaka, Zambia. The use of different predictive models developed using reliable scientific and engineering methods were considered to accurately plan for future maintenance and funding needs. The selection of the most suitable alternative model was governed by the resources and pavement historical data available. Ultimately a fuzzy-logic prioritisation model was used over analytical hierarchy systems owing to the lack of past standardised condition assessment records required to ensure the latter's reliability. The selected model utilised a Mamdani Inference Engine that accepts two input parameters; the Pavement Condition Index (PCI), the AGE of the Pavement within a 20 year design period and an output parameter; TREATMENT. The output is expressed as a percentage which is related to a treatment class legend that allow users to interpret the results in terms of actual maintenance activities. The AeroPave software was designed to also include a database to store pavement information and work history. A PCI survey was carried out at KKIA with results showing an overall average PCI of 84 for the surveyed areas, namely; the runway, main taxiway and apron. These results were catalogued and added to the systems' database. It can be said from the trends observed from testing of the optimal timing model using sample data derived from the PCI ratings for KKIA that it is possible to use AeroPave at KKIA to recommend the optimal timing for treatment application. Further work needs to done to refine the fuzzy-logic prioritisation to make it more accurate.