A SUB-BASE AND PAVING CONSTRUCTION

Abstract: A sub-base and paving construction for roads, streets and similar surfaces exposed to load, such as footpaths, pavements, parking lots, loading areas, sports grounds and the like. The construction consists of at least one drain pipe (2) embedded in a layer (1) of preferably fine-stone macadam, a layer (3) of coarse-stone macadam placed laterally of and on top of the layer (1) and a levelling layer (4) of fine-stone macadam on top of the layer (3) of coarse-stone macadam. A paving (5) of draining asphalt is placed on top of the levelling layer (4).

Description: A sub-base and paving construc ion. The subject invention concerns a sub-base and paving construction for streets, roads and similar surfaces exposed to load, such as footpaths, pavements, parking lots, loading areas, sports grounds and the like. When constructions of the kind referred to are to be built, a number of preliminary measures usually have to be taken to ensure adequate run-off, drainage and transport of rainwater and melted snow. Such measures may include constructing the wearing course in such a way that it slopes towards rainwater gulleys, or providing gutters with rainwater gulleys. In streets, the pavements, access roads and the like must be raised highly above the street level as well as be provided with kerbstones. However, since wheelchairs can pass over kerbstones and highly- raised pavements only with difficulty, the use of kerbstone and pavements obstructs the mobility of disabled persons. Subsidence due to load or frost often spoil the drainage facilities after a short while. Water that collects on the road in the orm of puddles due to poor drainage may cause serious aqua-planing accidents. To eliminate the cause of such accidents it is necessary to restore the surface to its original condition, either by applying a fresh paving on top of the old one or by stripping off the old uneven paving and applying a fresh one. In connection with this restoration work it is often necessary to adjust the level of the rainwater gulleys to that of the fresh road paving. In constructing the sub—base and paving of heavy-duty surfaces, such as roads and the like, conventional methods employ the application of several layers of gravel and. macadam on the sub-grade, and the level and slope of each individual layer have to be adjusted separately. In addition the various layers have to be adjusted to the nature of the subsoil and to estimated wear thereon from traffic, etc. In this connection asphalt having draining properties has been used as paving but paving of this kind makes use of expensive means g * n measures necessary in and nearby the sub-base and paving construction in order to drain off the water that seeps through the paving. It is also known to use a fabric-type of separation, layer known as geo-textile to stabilize poor soils in road and building constructions of various kinds. The purpose of the subject invention is to provide a sub-base and paving construction for streets, roads and similar surfaces that are exposed to heavy loads, which construction, in combination with a draining paving, is easier to*build, requires only simple drainage and run-off means and less maintenance than has hitherto been possible. The construction in accordance with the invention is characterised in that it comprises at least one drain pipe which is deposited on an excavated surface while supported in a bed of preferably fine-stone macadam, a layer of ' coarse-stone macadam surrounding the bed of fine-stone macadam on the sides of ftnfl on top of said bed, a levelling layer of fine-stone macadam on top of the coarse-stone macadam layer, and a paving of draining asphalt placed on top of the levelling layer. Owing to the sub-base and paving construction in accordance with the invention the surface-water drain system may b . largely replaced by a drain system including infiltration or seepage drains, which system is more simple and cheaper to install. It becomes possible to eliminate largely the use of kerbstones and similar raised borders, thus improving the environment, particularly for crippled and disabled persons. Owing to the structure of the sub-bas and paving construction the natural water equilibrium of subsoil layers is maintained, which lessens the risks of subsidence and frost-heave damages, which in turn reduces maintenance costs. Furthermore, the danger of aqua-planing accidents is reduced to a minimum. Even if wear on a roadway were to result in the elimination of the original surface levelness, this will not prevent rainwater and melted snow from being drained off through the roadway proper. The invention will be described in closer detail in the following with reference to two embodiments thereof illustrated in the accompanying drawings. In the drawings, Pigs. 1 and 2 are cross-sectional views of two alternative embodiments of the sub-base and paving construc tion in accordance with the invention, Pig. 3 shows a driveway/footpath and house entrance in a cross-sectional view, Pig. 4 is an alternative embodiment of the invention shown in Pig. 3, Pig. ■ 5 is a cross-sectional view of the construction in accordance with the invention used for a garage driveway and Pig. 6 shows a parking-lot area including an area for plants. The construction in accordance with Pig. 1 is built on top of an excavated surface, the sub-grade, and consists of a bed 1 of preferably fine-stone macadam enclosing a drain pipe 2, a layer 3 of coarse-stone macadam, a levelling layer 4 of fine-stone macadam covering the coarse-stone macadam layer 3, and a paving 5 of draining asphalt on top of the levelling layer 4. When the ground 6 is liable to settlement or subsidence a layer of a separation membrane, preferably a fabric known as geo-textile 7, may be deposited on top of the excavated ground surface or sub-grade before the sub-base and paving construction is built. By using a geo-textile layer to separate the sub-grade from the sub—base construction, the macadam is prevented from sinking into the sub-grade while at the same time clay or earth is prevented from rising up between the macadam stones. Consequently, there is no risk of capillary water being trapped in the sub-base, which thus forms an insulating layer preventing frost heave and frost cracks. Excavation of the ground 6 is made to ensure that the sub-grade slopes at a certain angle towards the bed 1 enclosing the drainage pipe 2. Rainwater and melted snow that is drained off through the asphalt paving 5 is carried away through the drain pipe 2. The asphalt paving 5 is laid out so as to slope at a predetermined angle towards the verges of the road on either side thereof. The verges are formed with the usual- banks 8 and 9. The right-hand road verge is also provided with an edge support 10. The embodiment illustrated in Pig. 2 shows the ground or sub-grade 6 having been excavated so as to slope towards the left side of the road where one section 11 of the sub-grade,has been excavated to a lower level than the rest This lower-level sub-grade section 11 is intended to serve as a delay storage to hold rainwater that seeps through the road surface. The water storage empties both through percolation to the underlying earth strata and through a drain. Like in accordance with the embodiment of Fig. 1, the road construction consists of a layer 3 of coarse—stone macadam, a levelling layer 4 of fine-stone macadam on top of the coarse—stone macadam layer 3, and a layer of draining paving 5 applied over the levelling layer 4. In areas where the ground conditions and the soil are poor a layer 7 of a geo-textile material may also be positioned on top of the excavated sub—grade. Also the asphalt paving 5 is laid so as to slope towards the left-hand road-side, as seen in Pig, 2. A pavement 12 at the right- hand side of the road may be arranged at a slightly higher level than the road paving 5 and be bordered by low-level kerbstones 13 that allow wheels of e.g. wheel-chairs and perambulators to pass over the stones easily. 'BUREA The embodiment of the sub-base and paving construction in accordance with the invention shown in Fig. 2 can be used for footpaths that are also used as driveways and equipped with invalid-chair adjusted building entrances, as shown in Pigs. 3 and 4. A building 14 has a foundation 14' and conventional means for runoff and drainage of rainwater via surface-water drains 15 and a pipe 15 ! . An entrance ramp 16 is constructed so as to slope away from the building 14 towards a pedestrian's footpath which may also be used as a driveway and which is paved with draining asphalt 5 and has a sub-base construction agreeing with the embodiment shown in Pig. 2. The entire footpath/ driveway including the excavated sub-grade 6, the sub-base and the paving slope towards the right-hand side of the path/driveway, at which side are provided a water storage and a drain pipe 2. The right-hand side of the path/driveway is provided with a vertical edge support 17. Pig. 4 shows an alternative arrangement consisting of a cemented or nailed-down border edge 13. Owing to the arrangement of the sub-base and paving construction in accordance with the invention border stones may be entirely dispensed with at the entrance side. Pig. 5 shows a sub-base and paving construction in accordance with the first embodiment illustrated in Pig. 1 when used in connection with a garage 18 and its adjoining driveway. The excavated ground surface (sub-grade) 6 slopes towards the bed 1 surrounding the drain pipe 2 whereas the sub-base construction including the draining paving 5 slopes away from the garage 18 and from the right-hand side towards the drain pipe 2. Thanks to the use of a construction in accordance with the invention it is possible to allow the garage surface to slope somewhat towards the left-hand side as seen in Pig. 5 without necessitating the installation of a separate drainage system at this side. Normal water runoff from vehicles will be filtered through the sub-base and paving and be fΪ RH4 OMPI drained off through the pipe 2 together with any rainwater. Consequently there is no need for-separate loor drains inside the garage 18. Pig. 6 shows an arrangement for a planting area 19 adjacent a parking lot. The sub-grade 6 is excavated so as to slope towards the planting area 19 beneath which area is excavated a water storage 20. A separation layer of a geotextile fabric 7 is positioned on top of the excavated sub-grade 6 so as to extend from the bottom of the water storage 20 and at an angle up to border supports 21 which delimit the planting area 19 from the parking areas. In the water storage 20 there is a bed 1 of fine- stone macadam, surrounding a drain pipe 2. To one side of and on. top of the bed 1 as well as on. the opposite side of the planting area coarse-stone macadam is deposited in a layer 3 sloping towards the planting area. The geo- textile separation layer 7 prevents the top soil 22 from penetrating down to the coarse macadam 3» However, rainwater, that seeps down through the top soil 22 and the draining asphalt paving 5 will collect in the water storage 20 and be drained off via the drain, pipe.2. Owing to the design of the sub-base and paving construction in accordance with the invention the building work may be faciliated in that one single layer 3 is applied in one step instead of applying, in accordance with conventional methods, several layers that must be levelled individually. Since predominantly coarse-stone macadam can be used a light-weight construction is obtained that exerts less load on the groun thus reducing the risks of settlement and subsidence damages. The macadam fraction makes it possible to use a vaulted configuration, resulting in a very strong sub-base construction. The construction in accordance with the invention also has the advantage of retaining the natural water equilibrium in the underlying earth strata. The building costs may be considerably reduced since the traditional surface water drains may be substantially dispensed with. This in turn reduces maintenance costs. In addition, these costs also decrease owing to the reduction of settlement and subsid-ence damages. The invention is not limited to the embodiments shown and described but may be further modified in a variety of ways within the scope of the appended claims. The geo- textile 7 is required only when ground conditions are poor and as a separation layer when planting areas are desired. The sub-base and paving construction may be used also for airstrips and runways, sport fields and the like. The thickness of the various layers obviously may be varied according to the requirements and positions of usage.

Claims: C I M S 1. A sub-base and paving construction for traffic surfaces such as streets, footpaths, parking lots, loading areas, sports grounds and the like, c h a r a c t e r i s e d" i n t h a t it comprises at least one drain pipe which is deposited on an excavated surface while supported in a bed of preferably fine-stone macadam, a layer of coarse-stone macadam surrounding the bed of fine-stone macadam on the sides of and on top of said bed, a levelling layer of fine-stone macadam on top of the coarse-stone macadam layer, and a paving of draining asphalt placed on top of the levelling layer. 2. A construction as claimed in claim 1, c h a r a c t e r i s e d by a separation layer of a fabric known as geo-textile in the form of a fine-mesh net, said textile layer positioned on the excavated surface (sub-grade) to separate said surface from the bed enclosing the drain pipe or from the coarse-macadam layer. 3. A construction as claimed In claim 1, c h a r a c t e r i s e d i n t h a t the drain pipe is connected to a rainwater pipe and/or a recipient, such as seepage (infiltration) drains.

Inventors: LARSSON ROLF
Applicants: LARSSON ROLF
Application year: 1982
Main classification: E01C3
IPC codes: E01C3, E01C11, E01C13, E01C15