HU192594B - PROCEDURE FOR PREPARING ROAD OR ROAD MOLD - Google Patents

Abstract

The subject of the proposal is a method for preparing a pavement base, in which a crushed stone base layer is spread on the prepared base level, compacted and provided with a joint filling layer. The essence of the proposal is that a lean concrete base layer (5) with a maximum thickness of 20 cm is first spread on the base layer (4) as a joint filling layer, and then the pavement base (3) is compacted (Figure 1).

Description

The present invention relates to a method of forming a paving slab, which is mainly intended for medium and heavy-duty pavements or, for example, pavements.

As it is known, in road construction the purpose of the paving slab is to support the pavement on the one hand and to distribute the wheel load of the vehicles to the underground structure on the other hand.

The main requirements for modern tiles are:

- Sufficient load capacity;

- Do not compact afterwards in such a way as to endanger the smoothness of the course;

- The base layer must be waterproof and its load capacity must not be significantly reduced by water and frost;

- As far as possible be able to handle construction traffic;

- Do not cause cracks in the asphalt pavement;

- Enable the economical use of local building materials and industrial by-products;

- The manufacturing and construction of your material should be as mechanized as possible.

(See, for example, Dr. Abraham: Road Traffic Manual, Volume I, Chapter 2.4.3, Technical Publisher, Budapest, 1978.)

In the past, "crushed stone foundations (i.e.," scattered foundations) were used for this purpose. Classified crushed stone, preferably Z55 / 80, should be used. The material of the crushed stone and macadam bases is spread out evenly and compacted by rolling by moistening until the crushed stone grains are wedged well together. In the meantime, the gaps are evenly filled with the required quantity and quality of material, for example, 2 to 4 cm thick sludge, sandy gravel and gravel. During rolling, the profile must be checked for correctness and unevenness must be eliminated. As a post-treatment, such cover is watered with water to compact.

The common disadvantage of crushed stone foundations is that they have low load-bearing and load-bearing capacity, are highly compacted during traffic, not water-tight at all, and only allow the use of local materials in the immediate vicinity of the quarries.

Another widespread type of paving slab is the so-called “lean concrete foundation. It is made of sandy gravel, crushed and graded stone or blast furnace slag. The binder is usually 350 cement. The mixture prepared in the mixer is spread by a grader or a finisher in a mirror that does not absorb water from the load-bearing concrete. However, compacting with a tire roller or vibrator must be completed before cement cementing begins. The lightweight concrete foundation is usually 13-25 cm thick under the pavements and at least 8 cm thick under the walkways.

The disadvantage of lean concrete foundations is that it does not cooperate with the asphalt pavement laid on it, since its coefficient of thermal expansion differs significantly from that of asphalt. Furthermore, such a fund is only capable of carrying out construction traffic once it has solidified. Its main disadvantage, however, is that on heavily trafficked roads, the thinner layers of asphalt are relatively tired and crumble than other pavements. In addition, these inevitable cracks are mostly transverse to practical experience. Relatively thick 14 to 15 cm asphalt layers are needed, but its higher load carrying capacity is not always possible. Once the substrate is ready, the casing can only be made after the required long cure time. Furthermore, dismantling and refurbishing is cumbersome and time consuming. (Dr. Ervin Nemesdy, Chapter 5.1, Book structure of roads and motorways, Budapest, 1971.)

It is an object of the present invention to overcome the above shortcomings, that is, to provide an improved cladding process which eliminates cladding of the cladding, and which results in a waterproof, dimensionally stable cladding and requires less effort than known solutions.

In order to solve this problem, we have started from a known crushed stone base, where the crushed stone base layer is laid to the base level, compacted and provided with a filler layer. This was further developed in accordance with the present invention by first applying a thin-layer concrete layer of up to 20 cm thick as a filler layer to the screed base layer and then compacting the screed. .

It is preferable to make the bottom spray layer at least 15 cm thick. Preferably, this can be pre-compacted before application of the lean concrete base layer. The lean concrete base layer should be made of B-100 grade concrete, with a thickness of 5-15 cm.

DETAILED DESCRIPTION OF THE INVENTION The invention will now be described in more detail with reference to the drawing and the following examples. embodiment is shown in section.

The process of the present invention provides a paving slab of equivalent thickness to the so-called "equivalent thickness", as described above, wherein the lower layer is a coarse screed and the upper layer is a lean concrete base. Thus, the concrete according to the invention also acts as a filler material and, moreover, provides an intermediate layer having a low compressive strength but a relatively low tensile strength between the lower spreading base layer and the upper lean concrete base layer.

As shown in the drawing, 1 earthwork in this case is provided with 2 beds, which are 10 cm sandy gravel. Thus, this bearing 2 is provided as the base prepared in this case, to which the cover according to the invention, referred to as 3, is placed.

According to the invention, the paving slab 3 comprises a lower base layer 4 and an upper lean concrete base layer 5 superimposed thereon. The intermediate intermediate layer formed between the two layers is denoted by 6. The lower base layer 4 is in this case made of crushed stone Z80 / 100 having a thickness of 20 cm, which can be spread, for example, by a grader.

After spreading, the scattered base layer 4 was pre-compacted with a heavy static roller. In the present case, the layer of crushed stone was watered to the extent of 0.2 m ³ water / m ³ . It should be noted, however, that watering is not necessarily necessary, since the process of the present invention does not necessarily require reduction of the crushed stone layer gap volume.

Subsequently, the upper layer of lean concrete 5 was prepared. The concrete dumped in a few places by the tipper truck (in this case B-100 grade concrete) in this case was spread by a spreading machine with a thickness of 10 cm and compacted with a vibrating roller for at least 40-50 minutes in 8-10 rounds. (A concrete finisher can be used instead of the spreading machine and the vibrating roller.)

-2192 594 takes place the most important step of the process according to the invention, namely the filling of the gap and wedging in the lower diffused base layer 4, while creating an intermediate intermediate base layer 6 of a thickness of a few cm. This forms a compact layer having a compressive strength approximately equal to the upper lean concrete base layer 5, which then passes almost gradually into the lower sprayed base layer 4.

Vibration compaction also moves the entire lower base layer 4, so that some cracking or compacting is expected from the gravel bed.

According to our experimental results, the present invention provides a cladding base 3 of increasing strength from the bottom to the bottom, with a slight increase in strength even above the upper lean concrete base layer due to the absorption of the cement milk. 15

Subsequently, with a few trowel passes, the smooth top surface of the tiles was formed. As a post-treatment, the upper lean concrete base layer 5 was watered in the usual manner for lean concrete foundations.

The cladding thus formed 3 is then covered with cladding 7, which in this case is 8 cm thick, in a manner known per se. (In the drawing, the center line of the track is denoted by 8.)

In our experience, the experimental pavement of the present invention did not experience any compaction even during traffic. Thanks to the intermediate transition base layer 6, excellent cooperation and connection is achieved between the lower base layer 4 and the upper base layer 5. Thus, no uneven movement was observed at the base. Further, the surface of the pavement base was flat and even, and the final level design of the track structure could have already started from this solid foundation. As a result, the need for precision in construction is reduced when the lower screed base layer 4 is made, since the exact size is maintained by the upper screed base layer 5. Further, the concrete foundation of the invention is insensitive to water and frost. For frost-sensitive and clayey soils approx. A bed of 10 cm sandstone is recommended. This prevents the soft clayey mud subsoil or soil from being pressed into the lower spreading layer 4 and effectively wedges the spreading layer 4 from below.

Perhaps the most important advantage of the present invention is that it does not cause cracks in the cover 7 above. The relatively thin upper lean concrete base layer 5, even with a higher compressive strength than required, is sufficiently densely cracked. Since only dense and thin cracks can form in the upper lean concrete base layer 5, they are still tolerated by the relatively elastic and flexible asphalt pavement, which means that the pavement 7 is not yet capable of cracking.

As an added advantage, the lower spreading base layer can be used well after rolling, ie it is suitable for construction traffic without wedging.

According to our calculations, the cover 55 of the present invention is illustrated by way of example. with a pavement width of 6 m, it achieves a cost savings of at least HUF 120,000 per kilometer traveled in 1982, compared to the traditional equivalent lean concrete foundation, which represents a very significant economic benefit.

Increasing dimensional accuracy is not only an advantage when classifying a road, it also reduces the amount of asphalt to be worked.

The process of the present invention can reduce construction time by up to half. The solid and dimensionally paving foundation also provides a way to use, for example, asphalt pavers, which can save significant road construction work 10.

Since the construction of a track structure is a decisive cost factor in road construction, and the paving foundation is also a decisive factor, the present invention consequently improves the complex process of road construction.

Here are some more examples.

Example 1

In the course of this, the construction of the surface of the track structure was carried out in substantially the same manner as the example described in connection with the drawing. The only difference was that the bedding layer was not applied separately, so the paving slab went directly to the soil. The lower base layer was made of 20 cm crushed stone Z55 / 8O and the upper lean concrete base layer was made of B140 quality 8 cm thick concrete layer. Practical experience has shown that this cover is very successful for Council trips. .

Example 2

A paving slab has been constructed for asphalt paved sports pitches in accordance with the process of the present invention. The procedural steps were essentially the same. The difference is that here, the lower screed base layer was made of Z35 / 55-S crushed stone to 10-15 cm thick, and the upper lean concrete base layer was made of B-100 concrete 6-8 cm thick. In the case of plastic coverings, Β-200 can be recommended for the upper lean concrete base layer.

Claims (3)

CLAIMS 1. A method of forming a pavement or road pavement layer by applying a crushed base layer of crushed stone to a prepared base layer, compacting and applying a gap filler layer, characterized in that the gap base layer (4) is at first 20 cm thick forming a slab-like slab concrete base layer (5) and simultaneously and thereafter compacting the paving slab (3). Method according to Claim 1, characterized in that the screed base layer (4) is pre-compacted before applying the lean concrete foundation layer (5). Method according to Claim 1 or 2, characterized in that the lean concrete base layer (5) is made to a thickness of between 5 and 15 cm. 1 drawing Figure 1 Published by: National Office of Inventions Published by: Zoltán Himer Head of Department Published by Technical Publisher COPYLUX Printing and Duplicating Small Cooperative -3192 594