Classifications

• • E—FIXED CONSTRUCTIONS
  • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
  • E01C—CONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
  • E01C3/00—Foundations for pavings
  • E01C3/003—Foundations for pavings characterised by material or composition used, e.g. waste or recycled material
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
  • E02D3/00—Improving or preserving soil or rock, e.g. preserving permafrost soil
  • E02D3/12—Consolidating by placing solidifying or pore-filling substances in the soil

Definitions

• the present invention relates to a method for producing a base course, in particular for road construction or as a stand space for buildings.
• arid zones In these areas, but also in areas with little precipitation, which are not yet (completely) deserts, so-called arid zones, are predominantly equal-grained, fine-grained sands in loose storage, which do not have sufficient capacity for road construction or other foundations. Due to their uniformity, they are not compressible. The shear strength is therefore very low. The cause of the low shear strength is the round grain shape and the uniformity of the sand.
• milled base course in the hot climatic zone Another problem with making the milled base course in the hot climatic zone is keeping it moist until the final setting takes several days.
• the milled layers must be prepared with sufficient water content and kept moist until the final hydraulic binding with high water levels, so that these layers do not burn in the hot sun and bind only partially hydraulically, resulting in considerable loss of strength.
• MBA residues are mainly fibrous wood and plastic residues with peat-like residual waste of coarse fiber structure with different grain size and length in a dry state. These residues accumulate in large quantities in mechanical-biological treatment plants and are not landfillable. If these materials are deposited in a landfill and blended, no strength is achieved and there is a high sensitivity to weather, as the light materials are washed away in the rain. This also applies if waste incineration slag is added to the MBT residues.
• the disbursements may be granular soil layers with too low a grain strength, e.g. Home burners or boiler ashes act. These soils are not sufficiently stable despite compaction because the grain breaks under load. Foundations of foundry sands, slag sand, blasting sand, etc. comparable to a uniform desert sand, due to their uniformity, do not have sufficient bearing capacity for foundations. Mixed-grained fillings, in which, on the other hand, ultrafine grain, silt occurs and which are additionally wetted, can not be compacted because of their high water content, since they soften during mechanical processing and even in the compacted state, assuming optimum water content for compaction, no adequate load-bearing capacity Give birth to buildings.
• BE-822838 A1 For example, a method for producing a base course is known in which the starting material is sewage sludge and in which the order of the method steps is different.
• the FR-1433508 A describes a method for producing a base course in which sand is mixed with slag, fly ash and lime.
• this document does not describe the mixing of the sand with broken refuse incineration slag of small particle size, the addition of 20 to 30 vol.% of water-containing mud or silt.
• the present invention is therefore based on the problem to provide a method in which open-porous starting materials of low shear strength can be used in structural layers for road construction or for other purposes even under extreme climatic conditions by physical grain supports in a particularly economical manner.
• the present invention solves this problem by a method for producing a supporting layer, in particular for road construction or as a stand space for buildings, with the steps specified in claim 1.
• the process according to the invention provides the following basic prerequisites for solving the abovementioned problem:
• the starting material is first mixed with broken refuse incineration slag having an average grain size of ⁇ 45 mm, preferably ⁇ 32 mm.
• Waste incineration slag of this size is capable of filling the open pores of the feedstock, thereby providing grain support and hence higher shear strength.
• the material mixture With the water-containing sludge, the material mixture, if necessary, mixed with a water carrier, so that the hydraulic setting can take place in the preferably already solidified support layer over several days without costly moisture retention.
• the material mixture can additionally be treated with seawater without causing damage to the load bearing capacity due to resulting salt structures.
• the water-containing sludge which may be used optionally has a cohesive soil with grain sizes of ⁇ 0.06 mm.
• the sludge may be, for example, sewage sludge or sludge.
• the water content of the slurry is preferably 75% by weight - 85% by weight, preferably 70% by weight - 80% by weight.
• the MBT residues or the above-mentioned fillings are then mixed with substitute building materials which achieve good compaction capability and high shear strengths by filling the microporous structure of the starting material.
• the material mixture is brought into a state by having a sufficient load capacity, so that it can be applied and compacted even in damp weather as a support layer.
• the materials mentioned as substitute building materials have a free lime content of 20% to 33% by volume.
• the grain size of the substitute building materials is preferably ⁇ 2 mm, up to a fine grain of ⁇ 0.06 mm. Substitute building materials with these properties contribute to grain support and, on the other hand, enable hydraulic bonding in the base course to further solidify it.
• the present invention relates to a support layer, in particular for road construction or as a support layer for buildings, which has been produced by one of the methods explained above.
• the open pore volume of the sand is preferably 30 vol.% To max. 35 vol.%. It has been found that the highest shear values are achieved if there is no overmixing when adding the split sand, i. H. no maximum filling of the pores takes place. The amounts added should therefore be 15% by volume, preferably 20% by volume, max. 30 vol.% Be. This takes into account that even more materials must be mixed into the sand pores.
• shear values of p 30 ° are determined, is achieved by a grain support with chippings a shear value of 38 ° to 42 °, depending on the rock strength of recycled materials. These shear values correspond to the shear strength of mineral mixtures, as used in Europe for road construction as minimum values.
• load carrying capacities such as those required for road construction materials for heavy goods traffic (E v2 ⁇ 150 MN / m 2 ) achieve. With such mixtures, however, carrying capacity values of E v2 ⁇ 80 MN / m 2 are already achieved.
• Substitute building materials achieved a further grain support up to the fine grain, ie a grain size of 0.06 mm, which already leads to an increase in strength after compression with homogeneous mixing.
• dry coal fly ash, fluidized bed ash, ladle slag or lignite ashes and also paper ashes are suitable.
• These substitute building materials are characterized in particular by the fact that they have a free lime content of 25%.
• the grain size of these replacement building materials is 0.01 to 1.0 mm, sometimes up to 2.0 mm. It is important that the substitute building materials are available in large quantities in substantially completely dry form similar to cement for such tasks. Moistened deleted replacement building materials of this type are less suitable for this purpose.
• the support layer produced in this way should be installed in layers in thicknesses of preferably 30-40 cm and compacted with heavy vibratory shell smoothing rollers weighing 10 - 15 t, preferably to 100% of the Proctor density.
• the hydraulic binding finally, takes place over several days. If the mixture is kept moist for hydraulic setting, optimal values are achieved after one week. The longer period of time is explained by the CO 2 absorption from the air required for the hydraulic setting, when the lime, which has been cleared by the water, changes to hardened lime. For this purpose, the CO 2 must first penetrate into the layer so that the required chemical reaction can take place. Due to the comparatively high strength, even before the hydraulic binding, the base course can already be exposed to medium loads during this time, whereby a rational implementation of further processing measures with machine assistance is to a certain extent possible.
• a slurry is preferably added to the base course mixture, which corresponds approximately to the grain size of a mixed soil of clay, silt and sand of a loess clay with grain sizes of 0.001 to 0.06 mm and up to 2 mm natural Schluffen has a very high water content.
• sewage sludge may be added as a hydrous soil to the hydraulic sealant of the order of the open pore size of the base course are about 20 - 30%, preferably 25%, without the support layer loses its carrying capacity values.
• the hydraulic setting retains its function under extreme climatic conditions of the hot sun and does not burn. Only on the surface of the Erdplanum the support layer is preferably to keep moist with enough water, which is why conveniently this base layers with a wear or cover layer, such as a road surface, overbuilt. Large volumes of water to moisturize the base course in the interior are not needed because the properties of the sludge are used as "dry water".
• Another example confirms the stabilizing effect of silt in the soil mixture.
• soil pressures correspond to load capacities of compacted gritty sand and gravel sand layers or building rubble materials with a grain size of on average between o and 45 mm, on which is usually established with equal soil pressures.
• the materials are homogenously processed in compulsory mixing plants and then compacted with heavy rollers after installation approx. 10t.
• the pore structure of this mixture is further filled and by adding said substitute building materials in an amount of 20 vol.% - 33 vol.%
• the Buildability, compaction capability, the required load-bearing capacity and the erosion and deflation resistance of the mixtures with MBA materials achieved.
• the carrying capacity values are 20 - 30 MN / m 2 after 14 days of service life; on the other hand, only values of 5-10 MN / m 2 were achieved with the garbage slag alone, which corresponds to a soft clay. When it rained, no more abrasion was produced on the surface conditioned with the abovementioned substitute building materials and sludge.
• the base courses have sufficient stability on embankments and sufficient strength, be it for further use or for driving over the materials for further proper layering with conventional earth-moving equipment, even in wet weather conditions. Due to the water-repellent properties of the MBT residues, the leachate recharge in the base area of the landfill is significantly reduced. Only by such a procedure, the above-mentioned governmental requirements for landfill deposition can be met.

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• Engineering & Computer Science (AREA)
• Structural Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Civil Engineering (AREA)
• Environmental & Geological Engineering (AREA)
• Agronomy & Crop Science (AREA)
• Architecture (AREA)
• Soil Sciences (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Mining & Mineral Resources (AREA)
• Paleontology (AREA)
• General Engineering & Computer Science (AREA)
• Processing Of Solid Wastes (AREA)
• Road Paving Structures (AREA)

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• 2004
  • 2004-10-29 EP EP11184515.2A patent/EP2468955B1/fr not_active Expired - Lifetime
  • 2004-10-29 ES ES04025845T patent/ES2401837T3/es not_active Expired - Lifetime
  • 2004-10-29 EP EP20040025845 patent/EP1655410B1/fr not_active Expired - Lifetime

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