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Lateritic fine-grained soils in road pavement base courses
314A 925316 Stress-strain analysis of karstic subsoil-slab (strip) footing system Malikova, T A; Pavlik, G N; Masin, S Y Proc Ninth Danube-European Conference on Soil Mechanics and Foundation Engineering, Budapest, 2-5 October 1990 P345-351. Publ Budapest: Akademiai Kiado, 1990 Rise in water table in karstic regions can lead to development of new cavities and surface deformation, which can affect superincumbent structures. A solution to the slab footing-karstic base interaction problem is presented in which footing and base are analysed separately. The GROS-3 computer code is used to predict the stress distribution around a karst-induced surface depression. The response of the slab footing to this loading is then examined. The procedure is applicable to design or stabilisation of footings.
Base courses and pavements 925317 Naturally-occurring but non-standard materials in low-cost road construction Metcalf, J B lnt J Geotech Geol Engng V9, N3/4, Sept~Dec 1991, P155165 Road materials are generally specified in terms of key features of grading, stone properties, fines content, and fines properties. Typical road material specifications are described. Where suitable in-specification materials are not readily available, use may be made of soft rock or weathered hard rock. Cases where such materials have been successful, generally for lightly trafficked roads in relatively dry (or well drained) conditions, are described. The need for careful construction control and rcalisation of the risks involved is noted. 925318 Lateritic fine-grained soils in road pavement base courses Nogami, J S; ViIlibor, D F lnt J Geotech Geol Engng vg, N3/4, Sept~Dec 1991, P167182 Lateritic soils are frequently found along road routes in tropical countries. They do not, however, conform to traditional specifications for subgrade materials. The geotechnical properties of these soils are described. A new set of the tests, the MCT (Miniature Compacted for Tropical soils) tests, has been developed to assess the suitability of tropical lateritic soils for pavement construction. Its use to examine sandy and clayey soils and their successful use in roads are described. Care must be taken in construction procedures and allowed traffic loading is subject to some limitations. 925319 Investigations in Kenya and Malawi using as-dug laterite as bases for bituminous surfaced roads Grace, H Int J Geotech Geoi Engng I/9, N3/4, Sept~Dec 1991, P183195 Trial sections of bituminous surfaced roads with as-dug laterite replacing stone or stabilised materials as the base course have been evaluated. Although the laterite does not conform to accepted specifications, the trial sections performed as well as did the 'standard' sections. Construction methods are described. A 4-6 week delay between base compaction and surfacing is required, during which weather and traffic or periodic wetting and rolling result in filling and closing of any
cracks in the base course. Surfacing is applied when the base is at about half optimum water content. Cost savings are significant. 925320 Towards understanding the behaviour of naturally-occurring road construction materials Toll, D G lnt J Geotech Geol Engng V9, N3/4, Sept~Dec 1991. P197217 Where quality aggregates for road building are not available or affordable, naturally occurring materials with increased fines content and higher plasticity than traditional crushed rock must be used. Soil suction and fabric then become important to subgrade behaviour. The concepts of these parameters are introduced and their influence on behaviour of road construction materials illustrated with reference to laboratory studies on a lateritic gravel and two calcrete gravels. These materials have been successful in lightly trafficked metalled rocks. Fines advantageously allow significant suction to develop and reduce permeability. 925321 Characterization and use of tropical gravels for pavement construction in West Africa Gidigasu, M D lnt J Geotech Geol Engng vg, N3/4. Sept~Dec 1991, P219260 Roads built in tropical countries using local materials should be designed and constructed bearing in mind the development and properties of these materials. The range of tropical gravels widely available for road building is described. A suitable program for their laboratory evaluation and characterisation is proposed. Pavement construction methods, particularly compaction procedures, for use with these materials are discussed. Performance details of these roads are presented. The development of specifications for assessment and use of tropical gravels as pavement materials is finally discussed. 925322 Evaluation of flowable fly-ash backfill. I: Static loading Peindl, R D; Janardhanam, R; Burns, F J Geotech Engng Div ASCE VI18, N3, March 1992, P449463 Trench backfill tests have been used to compare the performance of a typical compacted soil fill and a flowable fly ash fill. The test site is a series of parallel trenches traversing a service road. Instrumented pipe assemblies were installed in trenches filled with compacted soil or a concrete/fly ash slurry (ashcrete). Horizontal and circumferential strains and joint separation of the pipe assemblies were monitored during loading by the regular heavy vehicle traffic. The ashcrete demonstrated superior properties in terms of consistently reduced pipe strain and minimal settlement. A further advantage of ashcrete is ease of placement. 925323 Evaluation of flowable fly-ash backfill: lh Dynamic loading Peindl, R D; Janardhanam, R; Burns, F J Geotech Engng Div ASCE VlI8, N3, March 1992, P464474 Trench backfill tests used to compare performance of compacted soil and fly ash/concrete (ashcrete) slurry backfills are described. Instrumented pipe assemblies were installed in a series of parallel trenches traversing a service road, which were subsequently backfilled. Dynamic strains and joint loads resulting from normal vehicular traffic were monitored. Data are presented from the soil fill at two stages of compaction and
© 1992 Pergamon Press Ltd. Reproduction not permitted
Base courses and pavements 925317 Naturally-occurring but non-standard materials in low-cost road construction Metcalf, J B lnt J Geotech Geol Engng V9, N3/4, Sept~Dec 1991, P155165 Road materials are generally specified in terms of key features of grading, stone properties, fines content, and fines properties. Typical road material specifications are described. Where suitable in-specification materials are not readily available, use may be made of soft rock or weathered hard rock. Cases where such materials have been successful, generally for lightly trafficked roads in relatively dry (or well drained) conditions, are described. The need for careful construction control and rcalisation of the risks involved is noted. 925318 Lateritic fine-grained soils in road pavement base courses Nogami, J S; ViIlibor, D F lnt J Geotech Geol Engng vg, N3/4, Sept~Dec 1991, P167182 Lateritic soils are frequently found along road routes in tropical countries. They do not, however, conform to traditional specifications for subgrade materials. The geotechnical properties of these soils are described. A new set of the tests, the MCT (Miniature Compacted for Tropical soils) tests, has been developed to assess the suitability of tropical lateritic soils for pavement construction. Its use to examine sandy and clayey soils and their successful use in roads are described. Care must be taken in construction procedures and allowed traffic loading is subject to some limitations. 925319 Investigations in Kenya and Malawi using as-dug laterite as bases for bituminous surfaced roads Grace, H Int J Geotech Geoi Engng I/9, N3/4, Sept~Dec 1991, P183195 Trial sections of bituminous surfaced roads with as-dug laterite replacing stone or stabilised materials as the base course have been evaluated. Although the laterite does not conform to accepted specifications, the trial sections performed as well as did the 'standard' sections. Construction methods are described. A 4-6 week delay between base compaction and surfacing is required, during which weather and traffic or periodic wetting and rolling result in filling and closing of any
cracks in the base course. Surfacing is applied when the base is at about half optimum water content. Cost savings are significant. 925320 Towards understanding the behaviour of naturally-occurring road construction materials Toll, D G lnt J Geotech Geol Engng V9, N3/4, Sept~Dec 1991. P197217 Where quality aggregates for road building are not available or affordable, naturally occurring materials with increased fines content and higher plasticity than traditional crushed rock must be used. Soil suction and fabric then become important to subgrade behaviour. The concepts of these parameters are introduced and their influence on behaviour of road construction materials illustrated with reference to laboratory studies on a lateritic gravel and two calcrete gravels. These materials have been successful in lightly trafficked metalled rocks. Fines advantageously allow significant suction to develop and reduce permeability. 925321 Characterization and use of tropical gravels for pavement construction in West Africa Gidigasu, M D lnt J Geotech Geol Engng vg, N3/4. Sept~Dec 1991, P219260 Roads built in tropical countries using local materials should be designed and constructed bearing in mind the development and properties of these materials. The range of tropical gravels widely available for road building is described. A suitable program for their laboratory evaluation and characterisation is proposed. Pavement construction methods, particularly compaction procedures, for use with these materials are discussed. Performance details of these roads are presented. The development of specifications for assessment and use of tropical gravels as pavement materials is finally discussed. 925322 Evaluation of flowable fly-ash backfill. I: Static loading Peindl, R D; Janardhanam, R; Burns, F J Geotech Engng Div ASCE VI18, N3, March 1992, P449463 Trench backfill tests have been used to compare the performance of a typical compacted soil fill and a flowable fly ash fill. The test site is a series of parallel trenches traversing a service road. Instrumented pipe assemblies were installed in trenches filled with compacted soil or a concrete/fly ash slurry (ashcrete). Horizontal and circumferential strains and joint separation of the pipe assemblies were monitored during loading by the regular heavy vehicle traffic. The ashcrete demonstrated superior properties in terms of consistently reduced pipe strain and minimal settlement. A further advantage of ashcrete is ease of placement. 925323 Evaluation of flowable fly-ash backfill: lh Dynamic loading Peindl, R D; Janardhanam, R; Burns, F J Geotech Engng Div ASCE VlI8, N3, March 1992, P464474 Trench backfill tests used to compare performance of compacted soil and fly ash/concrete (ashcrete) slurry backfills are described. Instrumented pipe assemblies were installed in a series of parallel trenches traversing a service road, which were subsequently backfilled. Dynamic strains and joint loads resulting from normal vehicular traffic were monitored. Data are presented from the soil fill at two stages of compaction and
© 1992 Pergamon Press Ltd. Reproduction not permitted