PL215827B1 - Production method of concrete board for objects of traffic building industry - Google Patents

Description

The subject of the invention is a method of making a concrete slab for communication structures, in particular an airport, road, parking, maneuvering slab, foundation slab for rail, road and pedestrian traffic, and a bridge deck slab of repeatable concrete, reinforced concrete or prestressed concrete elements. and composite viaducts, transition slab for raids on bridge structures and / or for places where there is a sudden change in the stiffness of the ground of the communication route.

Known methods of making concrete airfield and road pavements, the so-called "wet method", consist in pouring concrete in a continuous manner to form a slab of a designed thickness that provides the desired load-bearing capacity. A known concrete slab is poured on a previously prepared foundation, generally made of a compacted and leveled ground base lined with geotextile and surface hardened with a layer of concrete.

In the above-described known method, it is necessary to cut the maturing concrete slab on the surface in order to ensure the formation of a regular pattern of shrinkage cracks in the desired places, which are then sealed with masses, for example hot bitumen, or with gaskets filling specially shaped cuts.

One of the methods of sealing specially shaped cuts in the plate with a pressed-in flexible cellular mass, ensuring tightness during thermal operation of the plate, is presented in the description of the invention GB. 855069.

It is well known that shrinkage cracks occurring during the contraction of the road slab during the maturation of concrete and changes in the width of these cracks may cause a number of unfavorable phenomena, such as cracking of the surface layer, often made of bituminous masses, which in turn causes accelerated destruction of the surface. by penetrating water where such cracks occur.

One method of protecting the road surface from the formation of large shrinkage cracks is disclosed in US Pat. No. 3680450. According to this solution, by appropriately shaping the surface joining the foundation with the slab, a series of small-spaced microcracks are obtained, which protects the bituminous paving layer of the road slab against damage.

Another known method of making airfield and road slabs is laying them out of prefabricated elements that are not prone to shrinkage cracks. The unfavorable phenomena accompanying the use of the communication object slab, made of prefabricated slabs, under thermal and dynamic loads, are eliminated by a number of solutions known from the patent literature.

One of the solutions known in this respect is the prestressing of airport aprons, described in the invention SU.1838496. The stress introduces compressive stresses in cross-sections along the entire length of the concrete slab, preventing the formation of cracks under thermal and dynamic loads, and causes a significant stiffening of the entire slab.

The displacement of the plate edges under the influence of thermal and dynamic operational loads can be leveled when, during the assembly of the communication object plate, the prefabricated plates are joined with rigid steel fasteners, transferring tensile stresses, in the manner presented in the JP patent description. 11350431 or in the application WO.05098139. A similar assumption underlies the solution disclosed in US 2002/0046524, in which the panels are joined using a ductile fiber-reinforced cement composite.

On the other hand, according to the solution known from JP.2005336881, free deformation of prefabricated panels under thermal and dynamic loads, but preventing the penetration of water into the joint between the panels, is possible due to the fact that a flexible rubber cover is screwed to the edge of the near-surface panels.

The foundations for rail communication routes are generally made in a manner similar to those used for concrete road surfaces, but an additional element that has been used as a base for decades is a massive base made of a layer of crushed stone, on which concrete or wooden sleepers with tracks are placed. .

In places where, along the route of a rail or road communication route, there is a sudden change in the stiffness of the ground, especially when driving onto bridge structures, the so-called transition plate. It is made of reinforced or prestressed concrete and rests with one end on the bridge abutment and the other on the ground. Subsequent layers, selected in accordance with the operational requirements, are then placed on the transition slab, which ensures a relatively smooth transition of the trail from one type of substrate to another.

Concrete slabs and substrates made of concrete are, as is well known, sensitive to deformations causing deformations exceeding the limit deformability of concrete, measured in fractions of a percent. The result of exceeding the limit deformability is concrete cracking and uneven settlement and keying of the separated sections of the slab. Also foundations made of compacted soil are susceptible to deformation when there is a locally weak base in their base.

The main disadvantage of laying the concrete slab of a communication object continuously, using the wet method, is the high time-consuming execution. The process from laying the concrete mass to putting it into service usually takes several weeks and is associated with the need to maintain the concrete, especially during unfavorable weather conditions. Difficulties in maintaining an appropriate technological regime in field conditions have a negative impact on the quality of the concrete slab made with this known technology. In addition, a continuous slab requires notches due to shrinkage processes and these notches result in a system after the concrete has matured, which works like free-laid prefabricated slabs and exhibits the same known imperfections under thermal and dynamic operational loads.

It is known that the basic imperfections of panels laid freely on a substrate, whether prefabricated or formed from wet-formed panels by cutting and shrinking processes, include susceptibility to thermal deformation. Panels subjected to uneven heating in day-night and summer-winter cycles buckle in the center or at the corners, which, with dynamic loads occurring during the operation of the facility, may lead to cracking of the panels and water penetration.

The freely laid boards are also susceptible to the so-called keying and reciprocal shifts due to thermal expansion of the plates and horizontal dynamic forces.

In all these cases, a significant problem is also the need to ensure the tightness of the panel joints in order to prevent water penetration and washing out of substrate particles and the formation of ice lenses under the concrete elements.

In the case of transition slabs, the main problem is the instability of the foundation, which causes a change in the support pattern of the slab and its frequent cracking and subsidence, resulting in additional unevenness at the edge of the bridge structure. The deformation of the base of the communication route on the border of the bridge, which increases with time, necessitates frequent and costly repairs.

On the other hand, in the case of composite bridges, ensuring a rigid connection of the load-bearing steel structure with the concrete deck slab causes many technical complications. The cooperation between these elements is ensured by steel connectors (splines), which, embedded in concrete, should ensure the condition of equal deformations in the horizontal section at the junction of both structural elements. The operation of a bridge structure constructed in this way under operational and thermal loads causes shear stresses in the steel connectors and generates significant tensile forces in the concrete bridge slab. For this reason, a relatively high percentage of reinforced concrete is required for the construction of the platform slab.

The implementation of this type of reinforced concrete platform slabs requires large financial outlays and is usually very time-consuming. This is especially noticeable during bridge renovations and during construction, when the replacement of the reinforced concrete slab or its execution entails closing the facility for several weeks, thus generating additional, often high social costs.

The essence of the invention consists in the fact that prefabricated concrete, reinforced concrete or prestressed concrete elements in the form of plates are used for the construction of the concrete slab of the communication object, which are joined (joined) by elastic-plastic joints, especially formed from a layer of permanently elastic polymer adhesive mass. plastic, in at least one layer or more preferably in more layers, stacked on top of each other.

The joints (dilatations) of the prefabricated elements of the base (bottom) layer are covered by prefabricated elements of the top layer, preferably in a regular pattern.

PL 215 827 B1

One layer of elastically-plastically connected prefabricated elements is used in special cases, for example, when the anticipated loads on the slab of the communication object are not large or when small mutual deformations of the joined slabs are allowed.

Prefabricated elements are placed directly on a leveled elastic foundation, in particular on a ground without foundation, or on a rigid foundation, or on a rigid base with a flexible spacer made of anti-vibration mats, formed, for example, of rubber chips or foamed polymers, and / or with a joint made of a layer of mass adhesive elastic-plastic.

In the method according to the invention, a permanently elastic-plastic polymer adhesive mass is used for the elastic-plastic joining of prefabricated elements with each other, and if necessary also with their rigid substrate, which after hardening shows parameters in the following ranges: Young's modulus lower than 200 MPa, strength compressive strength less than 20 MPa, tensile strength less than 6 MPa, shear strength less than 10 MPa, and deformability in the range of 1% to 400%.

The adhesive used in the solution according to the invention is characterized by the Young's modulus of elasticity many times lower, and its deformability many times higher than the concrete elements connected with it, and has a wide strength spectrum in the range comparable, but lower than the characteristic strength parameters of concrete.

It is furthermore advantageous if said adhesive comprises a filler made of quartz sand and / or rubber chips, carbon, glass, aramid or polymer fibers, allowing its properties to be modified.

The connection of prefabricated elements with joints made of layers of elastic-plastic adhesive mass causes an elastic "pull" of the newly formed plate of the communication object.

The advantageous feature resulting from the layered arrangement and elastic-plastic bonding of prefabricated elements is the reduction of unit stresses transmitted to the soil substrate, thanks to the distribution of the load transferred from the upper prefabricated element to the prefabricated elements placed in lower layers, occupying a much larger area.

The structure created by the method according to the invention is thus characterized by greater deformability, ductility and energy capacity - which allows for safe operation even under the influence of high thermal and dynamic loads.

Fixing the layer of prefabricated elements made according to the invention to a rigid substrate, for example on composite bridges or on old airport pavements, with the use of elastic-plastic adhesive, and preferably also with the additional use of flexible spacers between the substrate and the prefabricated elements, reduces the shear stresses present at the joint at rigid connections and ensures even load transfer.

Due to its flexibility, the polymer adhesive mass used in the invention reduces the maximum stress value and optimally distributes the stresses evenly over the entire joint surface. Due to the relatively large joint surface, the tensile strength of the joined elements is not exceeded. The elastic-plastic properties of the adhesive protect the joined elements against stress concentration in the place of surface unevenness. Under load, the adhesive mass allows for limited mutual deformation of the joined elements, thus dissipating the energy supplied to the system, increasing the vibration damping and equalizing the deformations arising in the contact layer with the concrete element. Moreover, the adhesive mass used in the invention has very good adhesion to concrete and steel, and ensures a tight connection of concrete elements, even with large deformations.

The shapes of the prefabricated elements used in the solution according to the invention can be rectangular, which is advantageous for communication systems with a small width, or square - especially advantageous for communication systems with large widths and airport aprons.

A further development of the invention consists in the use of prefabricated elements in the shape of a regular hexagon, arranged in layers in the form of a "honeycomb". Such a shape of the element ensures an optimal distribution of internal forces in a freely supported element, reducing the formation of stress concentration in the corners with thermal deformation, which is observed

In elements of square shape. Moreover, the "honeycomb" form ensures the most favorable spatial arrangement of the system.

Another development of the invention, ensuring stiffer spatial cooperation between the layers of prefabricated elements, consists in joining the elements with flexible point connectors, especially rods, embedded by means of a permanently elastic-plastic polymeric mass in the holes made in the panels. Said rod openings are made in the prefabricated elements substantially perpendicular to their surfaces.

The permanently elastic-plastic polymeric mass used in the method according to the invention has parameters in the following ranges: Young's modulus lower than 5 GPa, shear strength lower than 20 MPa, tensile strength lower than 25 MPa, and deformation within the range from 1% to 30 %.

Preferably, said anchoring mass comprises a filler made of quartz sand and / or rubber chips, carbon, glass, aramid or polymer fibers, allowing its properties to be modified.

Thus, the anchoring mass is characterized by a lower Young's modulus of elasticity and a higher deformation than the joined concrete elements, and has strengths higher or close to the characteristic strength of concrete.

Due to its flexibility, the anchor mass reduces the maximum stress value and optimally distributes the stress evenly over the entire surface of the rod-concrete connection. The elastic-plastic properties of the anchor mass protect the connected elements against stress concentration, and under load, they allow for limited deformation of the connected elements, thus dissipating the energy supplied to the system, increasing vibration damping and equalizing deformations arising in the contact layer with the concrete element.

In places where a significant weakening of the subsoil is expected, according to the invention, a mesh of carbon, glass, aramid or polymer fiber strips is introduced, glued on an anchoring polymer mass to the lower base surface of the lowest layer of prefabricated elements, which reduces the deformation of the system on the surface.

The sandwich systems made of prefabricated panels can also be covered with a wearing surface laid directly on them or on a surface reinforcing element, especially a geotextile or aramid mesh.

The method according to the invention is approximated by the examples of airport runway realizations presented below and by the attached drawings, where:

- Figure 1 shows a schematic top view of an array of rectangular prefabricated elements forming the slab of an exemplary road communication object,

- fig. 2 shows the section A-A in fig. 1 through a two-layer system of prefabricated elements forming the plate of the communication object,

- fig. 3 shows the section A-A in fig. 1 through a three-layer system of prefabricated elements forming the plate of the communication object,

Fig. 4 shows diagrammatically in plan view a detail of the arrangement of the rectangular prefabricated element of the upper layer on the expansion joint of the lower layer in the exemplary road communication object shown in Fig. 1,

Fig. 5 shows diagrammatically in plan view a detail of joining by point flexible connectors of rectangular elements of prefabricated slab layers in the exemplary road communication facility shown in Fig. 1,

- fig. 6 shows the section B-B in fig. 5 through a two-layer system of prefabricated elements forming the plate of the communication object, connected by flexible point connectors,

Fig. 7 shows a section B-B in Fig. 5 through a three-layer system of prefabricated elements forming the plate of the communication object, connected by flexible point connectors,

Fig. 8 shows a schematic plan view of an arrangement of square prefabricated elements forming the apron of an exemplary airport, maneuvering yard or wide road communication facility,

Fig. 9 shows the section C-C in Fig. 8 through a two-layer system of prefabricated elements forming the plate of the communication object,

Fig. 10 shows the section C-C in Fig. 8 through a three-layer system of prefabricated elements forming the plate of the communication object,

PL 215 827 B1

Fig. 11 shows diagrammatically in top view a detail of the arrangement of the square prefabricated element of the upper layer on the expansion joint of the lower layer in the exemplary communication object shown in Fig. 8,

Fig. 12 shows diagrammatically in plan view a detail of the joining by point flexible connectors of square elements of prefabricated plate layers in the exemplary communication object shown in Fig. 8,

Fig. 13 shows a section D-D in Fig. 12 through a two-layer system of prefabricated elements forming the plate of the communication object, connected by flexible point connectors,

Fig. 14 shows a section D-D in Fig. 12 through a three-layer system of prefabricated elements forming the plate of the communication object, connected by flexible point connectors,

- Fig. 15 shows a schematic plan view of an arrangement of hexagonal prefabricated elements forming the slab of an exemplary parking lot, maneuvering or road communication object,

Fig. 16 shows the section E-E in Fig. 15 through a two-layer system of prefabricated elements forming the plate of the communication object,

Fig. 17 shows the section E-E in Fig. 15 through a three-layer system of prefabricated elements forming the plate of the communication object,

Fig. 18 is a schematic plan view of a detail of the positioning of the hexagonal top layer prefabricated element on the bottom layer dilatation in the exemplary communication object shown in Fig. 15,

Fig. 19 shows diagrammatically in top view a detail of the joining by point flexible connectors of hexagonal elements of prefabricated panel layers in the exemplary communication object shown in Fig. 15,

Fig. 20 shows a section F-F in Fig. 19 through a two-layer system of prefabricated elements forming the plate of the communication object, connected by flexible point connectors,

Fig. 21 shows a section F-F in Fig. 19 through a three-layer system of prefabricated elements forming the plate of the communication object, connected by flexible point connectors,

- Fig. 22 shows an exemplary arrangement of the arrangement of the reinforcing mesh strips under the communication object plate, arranged from square prefabricated elements,

- fig. 23 shows an exemplary arrangement of the arrangement of the reinforcing mesh strips under the plate of the communication object, arranged from hexagonal prefabricated elements,

- Fig. 24 shows a section G-G in Fig. 22 through a two-layer system of square prefabricated elements forming the slab of the communication object, showing the weakened substrate,

Fig. 25 shows a section H-H in Fig. 23 through a two-layer system of hexagonal prefabricated elements forming the slab of a communication object, showing the weakened substrate,

Fig. 26 shows the section G-G in Fig. 22 through a three-layer system of square prefabricated elements forming the slab of the communication object, showing the weakened substrate,

Fig. 27 shows a section H-H in Fig. 23 through a three-layer system of hexagonal prefabricated elements forming the slab of a communication object, showing the weakened substrate,

Fig. 28 shows a top view of the pavement on an exemplary foundation slab made of square prefabricated elements,

- Fig. 29 shows the section J-J in Fig. 28 through the pavement on a three-layer arrangement of square prefabricated elements forming the base plate.

On the marked out area of the planned location of an exemplary runway, the known foundation 1 of compacted soil is made in accordance with the rules of construction practice.

The location of the prefabricated elements 4 of the base, lower layer 2 is marked on the surface of the foundation.

In the example presented, these elements 4 were in the form of square plates with dimensions

2.5 x 2.5 m and 18 cm thick and made of prestressed concrete. The thickness of the joined boards has been designed with regard to load capacity.

In this example, the elements 4 are arranged in two layers 2 and 6, in a regular pattern as shown in fig. 8 and fig. 9, with the centers of the elements 4 forming the upper layer 6

The runway plates are positioned substantially above the locations where the tops of the four adjacent prefabricated plates of the lower layer 2 of the elements 4 lie.

The elements 4 were placed on the prepared surface of the foundation 1, creating a basic, lower layer 2, so that between the elements 4 there were expansion gaps 5 1 cm wide. These gaps were then filled over their entire height with adhesive 3.

Next, the position of the arrangement of elements 4 of the second, upper layer 6 was marked, after which a thin mat 13 of foamed polyurethane (PUR) was laid on the surface of the base layer 2, and the elements 4 according to Fig. 8 and Fig. 9 were placed on top of it, so as to cover the expansion joints the slots 5 of the base layer 2. The slots 5 of the upper layer 6 were then filled with adhesive 3.

In another embodiment of the runway, during the ground conditions reconnaissance, it was found that there was an interlaying of the weak ground under the defined runway, for example over a length of 40 m.

At this point, on the surface of the known foundation 1 made of compacted soil and a concrete layer, a mesh of carbon fiber strips 10 was laid with an axial spacing of 1.25 x 1.25 m - according to Fig. 22 and Fig. 24, so that it covers the width of the runway and along the runway overlapped by 10 m on each side beyond the boundary of the soil layer.

On the surface of the tapes 10, a layer of the anchoring compound 9, modified with a 10% addition of quartz sand, was applied, and the entire surface of the base 1, also between the tapes 10, was covered with a thin layer of adhesive 3.

On the surface prepared in this way, the elements 4 are arranged to form a basic, lower layer 2 in the configuration shown in Fig. 22 and Fig. 24, and to leave expansion gaps 5 1 cm wide, as in the first example, between the elements 4. These gaps were then filled over their entire height with adhesive 3. The position of the arrangement of elements 4 in the next, upper layer 6 was then marked out, after which a thin PUR mat was placed on the surface of the base layer 2 and the elements 4 were laid in accordance with Fig. 24, so as to cover expansion joints 5 of the base layer 2. The expansion joints 5 of the layer 6 were then filled with adhesive 3.

In a further embodiment of the invention, based on the above-described methods of executing the runway, a thin PUR mat was laid on the surface of the upper layer 6, after filling the gaps 5 with adhesive 3, in order to obtain the strip plate with increased strength and to additionally stiffen the layers of elements 4 to each other. the elements 4 of the top layer 7 are arranged according to fig. 8 and fig. 10 so as to cover the expansion joints 5 of the upper layer 6. Then the expansion joints 5 of the top layer 7 are filled with adhesive 3. After the adhesive 3 has cured, drilled perpendicular to the surface of prefabricated elements 4 holes with a diameter of 20 mm and a depth of 50 cm. Into these holes, after blowing with air, bars 8 of ribbed steel with a diameter of 6 mm were glued onto the anchoring mass 9, as illustrated in Fig. 12 and Fig. 14. Finally, a bituminous paving layer 11, reinforced with geotextile 12 - was laid on the surface of the slab. according to Fig. 28 and Fig. 29.

It is understood and obvious that the examples presented above are merely an illustration of some basic possibilities for carrying out the invention and therefore cannot be considered as limiting the essence of the presented solution.

Claims (11)

The method of making a concrete slab for a communication construction object from prefabricated concrete, reinforced concrete or prestressed concrete elements, in the form of slabs and laid in layers, at least in one layer, on a previously made base layer of compacted soil, aggregate or concrete, or on a prepared the existing concrete or steel substrate, whereby after laying the basic layer of prefabricated elements, separated by expansion joints and forming a selected geometric system, expansion joints of the basic layer are filled, and, if necessary, further layers of prefabricated elements are laid on the made primary layer, and then the expansion joints of these layers, characterized in that the prefabricated elements (4) are bonded to each other and preferably to the base layer (1) or to the existing concrete or steel substrate, with elastic-plastic joints using the adhesive polymer mass (3) permanently elastic-plastic, which after hardened zeniu shows parameters in the following ranges: Young's modulus less than 200 MPa, compressive strength less than 20 MPa, The tensile strength is less than 6 MPa, the shear strength is less than 10 MPa and the deformation is between 1% and 400%. 2. The method according to p. A method according to claim 1, characterized in that the prefabricated elements (4) are arranged in one layer (2) or two layers (2; 6) or in three layers (2; 6; 7), separated from each other and / or from the base layer or from base, flexible spacers (13) and / or elastic-plastic joint made of the adhesive layer (3). 3. The method according to p. A method according to claim 2, characterized in that the prefabricated elements (4) are arranged such that the elements (4) of the upper layer cover the joints of the elements of the lower layer, preferably in a regular pattern. 4. The method according to p. 2. A method according to claim 2, characterized in that the flexible spacers (13) are in the form of vibro-insulating mats, in particular of rubber shavings or foamed polymers, whereby, at least on a part of their surface, the spacers (13) are elastically-plastically connected to the adjoining prefabricated elements (4). 5. The method according to p. The prefabricated elements (4) are rectangular or square shaped. 6. The method according to p. 3. A method according to claim 3, characterized in that the prefabricated elements (4) have the shape of a regular hexagon and are arranged in a geometric pattern resembling a honeycomb. 7. The method according to p. 1 or 2, or 3, or 4, or 5, or 6, characterized in that the layers (2; 6) and (2; 6; 7) of the prefabricated elements (4) are welded together in a direction substantially perpendicular to the surface to be performed slabs with point flexible connectors. 8. The method according to p. 7, characterized in that the point flexible connectors are bars (8), embedded in openings substantially perpendicular to the surface of the layers, using the permanently elastic-plastic anchoring polymer mass (9), which after hardening shows parameters in the following ranges: Young's modulus lower than 5 GPa, shear strength less than 20 MPa, tensile strength less than 25 MPa and deformation in the range of 1% to 30%. 9. The method according to p. The method of claim 1 or 8, characterized in that the adhesive polymer mass (3) and / or the anchoring polymer mass (9) comprises a filler made of quartz sand and / or rubber chips, carbon, glass, aramid or polymer fibers. 10. The method according to p. 1, 2, or 3, or 4, or 5, or 6, or 7, or 8, characterized in that before the base layer (2) of the prefabricated elements (4) is placed, on the surface of the base layer (1) or the substrate, a web of tapes (10) made of carbon, glass, aramid or polymer fibers, which is attached to the base layer (2) by means of an anchoring polymer mass (9). 11. The method according to p. 1 or 2, or 3, or 4, or 5, or 6, or 7, or 8, or 10, characterized in that a surface layer (11), especially bituminous, is laid on the surface of the panel made of prefabricated elements (4) , with a mesh or with a plastic or fiber mat (12).