MXPA00011962A - A method of stabilising the ground in road construction work - Google Patents

Abstract

The invention is characterised by mixing cement thoroughly with a microfill agent and possibly also a water reducing agent to obtain a highly-reactive and dry cement mixture;blending the cement mixture with at least one of the materials soil, clay or stone and possibly also water;spreading the blend on the ground (3, 8) to a thickness of at least 15-30 centimetres;causing the blend (4, 9) that is spread out on the ground to contain sufficient cement mixture so that after compaction said blend will have a compressive strength of at least 5 MPa after 28 days;and laying a roadbed (5, 10) on the blend (4, 9) subsequent to said blend having cured.

Description

METHOD TO STABILIZE THE TERRAIN IN THE ROAD CONSTRUCTION WORK • The present invention relates to a method for stabilize the terrain in the road construction work, the method is applied to the construction of new roads, or superhighways, and to the reinforcement of existing roads or superhighways. When new roads are built, it is necessary to stabilize weak subsoils. The muddy soil and the cohesive soils whose final support strength is too poor to support the construction of a new road are usually dug to a solid base and the resulting cavity is filled with suitable material, as be friction ground. When the need to dig to extreme depths to reach a solid base, for example depths that • exceed five meters, the excavation and filling is combined with compression of a heavy filler material such as rock. 20 When the weight of the heavy filling material becomes greater than the resistance of the underlying soil, the soil is compressed on one side. Normally it is necessary to apply an overload to the last section of the road, to push the masses, it is usually necessary to leave the overload in place for a period of 6 to 12 months, before being able to withdraw it. Extremely fine land is also excavated. The depth at which these lands are excavated will vary with climatic zones and also with respect to the leveling or uniformity of the finished road. These lands can be excavated to a depth of approximately two meters. Pronounced layers of clay soils can be cemented (anchored) or drained vertically. Of the aforementioned methods, the excavation of inadequate soils and the filling with suitable soils is the safest and often the most economical method. However, the method causes the environment to be loaded with excavated soil, etc., since these masses must be dumped in distant heaps and adequate masses taken from the distant deposits. The environment with these is charged by the extensive transportation of excavated and convenient materials. The support capacity of a road is usually the main problem in the reconstruction of existing roads. This applies mainly when a gravel road must be improved for a surfaced road. The upper construction of the road is usually replaced in these cases. Otherwise, the upper construction of the road increases with another construction, to obtain the desired support capacity. This procedure also requires taking masses from an adequate reservoir and • normally intense transportation. The present invention considerably reduces the need to excavate, fill and transport materials, both in the construction of new roads and when the support capacity of an existing road is increased. The present invention thus relates to a method for stabilizing the ground in the work of • 10 road construction, and is characterized by intensely mixing a cement with a micro-filling agent and optionally also with a water reducing agent, to obtain a highly reactive cement mixture, combining the cement mixture with at least one of the materials earth, clay or stone, and possibly water; deposit the mixture on the ground at a thickness of at least 15-20 centimeters; make the deposited mixture contain enough cement to obtain a compressive strength of at least 5 MPa 28 days after the compaction; and place a firm on top of the deposited mixture after curing the mixture. The invention will now be described in more detail with reference to the exemplary embodiments thereof and also with reference to the accompanying drawings, in which: Figure 1 illustrates an improved highway according to the invention; and Figure 2 is a cross-sectional view of a newly constructed road according to the invention. The present invention relates to a method to stabilize the ground in the construction of new roads and also existing roads where the support capacity of the land is insufficient or where there is a serious risk of susceptibility to freezing. According to the invention, the cement mixes perfectly with the micro-filler and possibly also a water reducing agent, to obtain a highly reactive, anhydrous cement mixture, the cement mixture is then combined with at least one of the materials earth, clay or stone and possibly also water to form a so-called mixture, where the material is taken from the ground on which the road must be constructed or from the surface layer of an existing road. The resulting mixture is deposited on the ground at a thickness of at least 15-30 centimeters. According to the invention, the mixture deposited on the ground is made to contain enough cement mixture to obtain a compressive strength of at least 5 MPa 28 days after compaction. A firm of traditional material is deposited in the upper part of the mixture after curing the mixture.

By a mixture of highly reactive, anhydrous cement, according to the aforementioned and in the clauses is meant a mixture of cement of the kind obtained by the • process described in the specification of European Patent No. EP 0696262 or a cement mixture that has been treated according to a corresponding process to obtain a compressive strength corresponding to that mentioned in EP 0696262. The specification of European Patent No. EP 0696262 • 10 describes a method to produce cement that can be used to produce paste, mortar, concrete and other high-support cement-based materials with reduced water content, high mechanical strength and density, and rapid resistance development. The method includes the mechanical-chemical treatment of cement and consists in the mechanical treatment in two stages of a cement mixture and at least a two-component • components, the first component is a micro-filler containing silicon dioxide and the second component is a polymer in the form of a water reducing agent, powder. The cement and / or the second component are mixed in the first stage in an anhydrous state, whereby the particles in the first and / or in the second component are adsorbed on the cement particles. The mixture obtained In the first stage, in the second stage, it is treated in a crusher in which the particles in the mixture are subjected to a large number of shock impulses that change the directions in a rapid sequence and with this the modification of the properties originates. surface of the cement particles in the form of a considerable increase in surface energy and chemical reactivity. The treatment in the second stage is continued for a sufficient time for a bucket of cement paste having a lateral length of 20 mm and compressed perfectly under vibration and cured at + 20 ° C under closed conditions [sic] to obtain a resistance to the compression in a day equal to at least 60 MPa. The cement used is Portland cement. The micro-filler may, for example, be ash dust or some other commercially available micro-filler. The water reducing agent can be any commercially available water reducing agent, for example the agent marketed under the name "Mighty 100". It has already been said that it is possible to add water. The amount of water needed, of course, will depend on the water content of the separated surface layer and mixed with the cement mixture. The person skilled in the art will have no difficulty in adding the correct amount of water to obtain the correct ratio of water / cement. According to a preferred embodiment, the weight ratio of the cement to another material or materials in the deposited mixture is from 5%: 95% up to 30%: 70%. According to one embodiment, the upper layer of an existing bed is removed. This layer will normally contain gravel and sand. The layer is usually removed with the help of a road grader, chopper or cutting machine adapted to lift the surface layer of the road. The cutting machine can be dragged by a tractor or similar vehicle. The surface layer is conveniently removed at a depth from about 15 centimeters to 50 centimeters. The separated surface material is mixed with the cement mixture and possibly also water, after which the resulting mixture is deposited on the firm. This is illustrated in Figure 1. The separated material can be mixed with the cement mix in a cement mixer. The resulting material can be applied to the road surface, emptying the material on the surface. Simple forms can be installed on the sides of the road surface to limit the width and length at which the mixture is deposited. The mixture deposited on the road surface will preferably be compacted to impart sufficient mechanical strength thereto. This compaction may be effected by vibrating the deposited mixture in a known manner. According to a preferred embodiment, this * Compaction is done in a way to produce discoidal elements that can then be placed on the ground. Figure 1 is a cross-sectional view of a road or superhighway existing after the treatment according to the method of the invention. The reference number 1 identifies a solid base, for example a rock base, the reference number 2 identifies the subsoil that needs is stabilized, and the reference number 3 identifies the previous sign. The subsoil may consist of sand, clay, different lands or materials. Reference number 4 in Figure 1 identifies the deposited mixture of the cement mixture and the first layers of the road surface. Reference number 5 identifies a traditional sign that has been deposited after material 4 has been cured. • According to another modality, the existing terrain material, such as soil, clay and sand, can be They remove when a new highway or superhighway is built and mixed with the cement mixture and possibly also water, after which the resulting mixture is deposited on the ground to form a foundation for a future firm. The steps of removing the The material, mixing the material with the cement mixture, compacting the mixture and applying the mixture to the ground can be carried out in a manner corresponding to that described above. Figure 2 is a cross-sectional view of a newly constructed road where the present invention has been applied. The reference number 6 identifies a solid base, for example a rock base, the reference number 7 identifies the ground that needs to be stabilized, and the reference number 8 identifies a surface layer of the ground. The subsoil may consist of sand, clay, different lands or other material. The reference number 9 in Figure 2 identifies the deposited mixture of the cement mixture and the surface layer material. Reference number 10 identifies a traditional sign that has been deposited after it has healed the material 9. According to a preferred embodiment with respect to the improvement of an existing road and the construction of a new road, the compacted mixture is dispersed on the ground to a width exceeding the width of the road in construction. It has been found that when a surface layer of an existing road is used and when the terrain material is used in the construction of a new road, these materials react with the mixture of highly reactive cement to form a plate or slab 4.9 of such high mechanical strength as to sufficiently stabilize the subsoil. This avoids the need for the complicated and disadvantageous stabilization methods described above. The stabilization of the masses in the trajectory path changes the properties of the masses to reduce the susceptibility to freezing and to greatly increase the support capacity of the road, thereby making it suitable for road construction purposes masses that were previously inadequate for this purpose. It also reduces the irregular placement of the firm. In the case of very weak subsoils, the stabilized material can be supplemented with reinforcement means, for example in the form of known mats or reinforcement networks. In this way, the stabilization allows to build a road on a very weak subsoil without the need for excavation that harms the environment and also in an efficient way in costs. Existing roads that have a low bearing capacity can be stabilized to obtain a necessary support capacity simply by applying a thin support layer, without the need to excavate or displace the earth or apply thick superstructures of refined natural gravel or stone taken from deposits far. It will be evident that it is possible to mix new material such as sand or gravel with the surface material that is mixed with the cement mixture. Although the invention has been described in the foregoing with reference to exemplary embodiments thereof, it will be understood that it is possible to make variations with respect to the construction work of the road. For example, a thin layer of sand or gravel deposited on the future road can be leveled to form a flat surface on which the mixture can then be dispersed. Therefore, the invention is not limited to the aforementioned and illustrated embodiments thereof, since it is possible to make variations within the scope of the following clauses.

Claims (7)

1. A method to stabilize the ground in the work of • road construction, characterized by mixing 5 cement perfectly with a micro-filler agent and possibly also a water reducing agent to obtain a mixture of highly reactive and anhydrous cement; combine the cement mixture with at least one of the earth, clay or stone materials and possibly also water; 10 Disperse the mixture on the ground (3, 8) to a thickness of at least 15-30 centimeters; make the mixture (4, 9) that was dispersed on the ground contain enough cement mixture so that after compaction the mixture has a compressive strength of at least 5 MPa 15 after 28 days; and depositing a firm (5, 10) on the mixture (4, 9) after the mixture has cured.

2. The method according to claim 1, characterized by removing the upper layer of an existing firm (3) and mixing the material of the layer with the mixture. 20 of cement and possibly also water, and then deposit the resulting mixture on the firm (3).

3. The method according to claim 1, when a new road is constructed, characterized by removing the material from the present terrain (8), such as earth, clay and 25 stone and mix the material with the cement mixture and possibly also water, and then deposit the resulting mixture on the ground to form a foundation (9) | for a firm future, superimposed (10).

4. The method according to claim 1, 2 or 3, characterized in that the weight ratio of the cement to another material in the deposited mixture is from 5%: 95% up to 30%: 70%.

5. The method according to claim 1, 2, 3 or 4 characterized by compacting the mixture to form a 10 element slab type and deposit the slab type element (4, 9) on the ground. The method according to claim 1, 2 3, 4 or 5, characterized in that the compacted mixture is deposited on the ground to a width exceeding the width of the 15 highway or future road. 7. The method according to any of the preceding claims, characterized in that the deposited mixture is reinforced with a corresponding reinforcing or strengthening network. twenty