DK179444B1 - Method of preparing a concrete pavement with a visual and textural pattern - Google Patents

Abstract

The invention relates to a method of preparing a concrete pavement with a visual and textural pattern, the method comprising the steps of i) applying a coherent concrete foundation by means of a wet concrete mixture over a defined preprepared area, the foundation having an upper part with an exposed concrete surface, ii) processing the wet concrete mixture by means of processing tools to obtain a coherent and substantially planar exposed concrete surface, optionally allowing the wet concrete mixture to partly dry for a period thereafter, iii) adding a powdered color pigment and a surface hardener to the concrete surface, iv) incorporating the powdered color pigment and the surface hardener into the upper part of the concrete foundation by means of processing tools, optionally allowing the concrete mixture to partly dry for a period of time thereafter, v) adding one or more additional and different powdered color pigments and/or a release agent to the surface, vi) imprinting the concrete surface by means of a number of visual and textural mats configured to face the concrete surface, the mats being pressed against the concrete surface partly into the upper part of the concrete foundation and thereby imprinting a visual and textural pattern upon the concrete surface resembling block paving, and vii) finalising by impregnating the imprinted surface with an impregnation liquid that penetrates the upper part of the concrete foundation comprising the surface hardener.

Description

DESCRIPTION

Accordingly, there has been provided a method of preparing a concrete pavement with a visual and textural pattern. The method comprising the steps of applying a coherent concrete foundation by means of a wet concrete mixture over a defined preprepared area where the foundation have an upper part with an exposed concrete surface. The wet concrete is processed by means of processing tools to obtain a coherent and substantially planar exposed concrete surface, optionally allowing the wet concrete mixture to partly dry for a period thereafter. A powdered color pigment and a surface hardener is added to the concrete surface, whereafter the powdered color pigment and the surface hardener is incorporated into the upper part of the concrete foundation by means of processing tools, optionally allowing the concrete mixture to partly dry for a period of time thereafter.

In the method one or more additional and different powdered color pigments and/or a release agent is added to the surface and the concrete surface is imprinted by means of a number of visual and textural mats configured to face the concrete surface, where the mats are being pressed against the concrete surface partly into the upper part of the concrete foundation. In this way a visual and textural pattern is imprinted upon the concrete surface and the paving resembles block paving.

As a final step, the imprinted surface is impregnated with an impregnation liquid that penetrates the upper part of the concrete foundation where the surface hardener is present.

One of the advantages of applying an impregnation liquid is that the concrete is not just treated on the surface, but also below the surface, since the impregnation liquid penetrates in a distance below the surface. This makes the structure in the upper part of the concrete foundation more withstanding against exterior and interior conditions, such as moisture, fungal, algae and lichen conditions. This is partly due to the nature of the impregnation liquid used and the fact that it penetrates into the pores of the concrete surface. This is parlticularly advantageous when the concrete has been imprinted according to the present invention. Small edges, grooves and fissures will particularly benefit from the impregnation according to the invention.

Traditionally, if sealants are used in the field of imprinted concrete pavements, it is in the form of a lacquer. A lacquer seals the entire surface and do not penetrate in the same distance into the concrete surface as the impregnation liquid according to the present invention. Hence, the lacquer remains mainly located on the surface of a concrete surface. This gives a visual appearance that may not be attractive to users of the concrete pavement. Also, a slippery and smooth surface will cause problems for users of the pavement, for instance during rain and winter times, something that is avoided by applying an impregnation liquid according to the present invention that penetrates the concrete material. Furthermore, a sealant in the form of a lacquer may be unevenly distribued on the surface and hence give rise to problems of water drainage, which is often caused by the texture of the imprinted surface. This is avoided when an impregnation liquid according to the invention is applied which penetrate the concrete and give rise to a pavement that has an evenly distributed sealant upon the imprinted surface. In addition, a lacquer needs to the removed and re-applied after a couple of years due to wear and tear of the surface. The impregnation liquid according to the present invention will last for at least a decade which was not expected and a great advantage compared to using a sealant. It requires less maintenance.

In the preparation method a powdered a color pigment and a surface hardener is added to the concrete surface and incorporated into the upper part of the concrete foundation by means of processing tools. Hence, the color pigment will be present in the upper layer of the concrete foundation and give a visual appearance at the surface. The surface hardener on the other hand provides a more dense and strong upper part of the concrete foundation. This will partly have the advantage of securing the color pigment better in the concrete surface and to give a stronger surface of the pavement.

Most surprisingly, it was observed that the impregnation liquid was able to penetrate the hardened concrete surface containing the color pigment and the surface hardener, even in light of the fact that the concrete was denser in structure. This was not expected and considered a great advantage of the present invention. One would have expected that the impregnation liquid would not penetrate the concrete in the same way as into concrete where no surface hardener is present. It is believed that the conventional wisdom in the art of imprinted concrete pavement is that only a lacquer, such as urethane or acrylate based lacquer, is possible to apply to a concrete material that is hardened beforehand for practical reasons. The benefit according to the present invention is thus that a strong surface is provided which has advantageous surface properties.

In the method, one or more additional and different powdered color pigments and/or a release agent is added to the surface. The advantage of adding one or more additional and different powdered color pigments is that a visual mosaic pattern may be made. This is a clear advantage compared to the patterns made in the prior art. The release agent may be another material, such as plastics applied on top of the concrete surface or may be a mineral or even the additional powdered color pigments.

According to the present invention, the imprinting step may involve a mat with for example wood grain, or light ground finishes found in cut or honed stone or regulat blocks. A decorative finishing mat includes a pattern having an impression of the decorative pattern formed thereupon. The mat is then pressed over the exposed surface of the concrete mixture to imprint the decorative pattern upon the exposed surface. The mat may have a custom designed template having protrusions such as rods, or indentations to uniquely form the decorative pattern. It is contemplated that protrusions, such as rods, may be rigidly attached to the mat through conventional means known in the art such as adhesives, welding, or fitting into grooves. It will be appreciated that the decorative pattern may have variations in depth, length, or size while still being formed by a single decorative finishing tool. Thereby, permitting a user to create such an aesthetically pleasing surface without the need for additional manpower. The mat according to the invention may be a rubber mat of various hardness known to a person skilled in the art.

In one embodiment of the invention, the impregnation liquid is distributed in the pores of the upper part of the concrete foundation having the surface hardener.

In one embodiment of the invention, the impregnation liquid is applied to the concrete surface and is allowed to penetrate the upper part of the concrete foundation having the surface hardener in a passive manner.

In one embodiment of the invention, a major part of the applied impregnation liquid is distributed in the pores of the upper part of the concrete foundation, such as more than 90% of the applied impregnation liquid.

In one embodiment of the invention, minor part of the applied impregnation liquid is located on the concrete surface, such as less than 10% of the applied impregnation liquid.

In one embodiment of the invention, the amount of applied impregnation liquid is more than 0.1 liter per square meter concrete surface and/or less than 0.2 liter per square meter concrete surface.

In one embodiment of the invention, the impregnation liquid penetrates more than 0.5 cm into the upper part of the concrete foundation, such as more than 1.0 cm.

In one embodiment of the invention, the upper part of the concrete foundation having the surface hardener has a density of more than 15 times the density of such concrete where a surface hardener is not added.

In one embodiment of the invention, the surface hardener comprises quartz mineral.

In one embodiment of the invention, the impregnation liquid comprises algae, fungal and/or lichens removal compounds.

The preferred method, which is not limiting to the invention, but serves as an example, commences by preparing the concrete surface. As an initial step the subgrade is prepared to a desired elevation and grade. The subgrade layer of a pavement is, essentially, the material underneath the pavement, also called the ground material. Generally, a subgrade requires some basic preparation for adaptation for construction purposes. Such preparation preferably comprises compacting the subgrade to approximately 90% compaction. Subsequent to being compacted, the subgrade is preferably covered with a layer of clean, moist fill sand which is preferably maintained at a minimum 10 cm thickness. Although the fill sand is not absolutely necessary for the method of producing the decorative concrete surface of the present invention, it is highly desirable to control the hydration process of the concrete. In order to increase the resultant strength of the concrete and reduce subsequent cracking of the same, reinforcement members such as wire mesh or rebar is/are positioned upon the layer of fill sand.

With the reinforcement members in place, a concrete mix or mixture is poured over the layer of fill sand and the reinforcement members such that the reinforcement members are encapsulated therewithin. The concrete mixture is poured to approximately for instance 10 cm thickness. Although variations in the concrete mixture are clearly contemplated, a preferred concrete mixture comprises 70% sand and 30% three-eighth inch mean diameter aggregate combined with six sack cement (two thousand pounds per square inch) or seven sack cement (three thousand pounds per square inch). Dependent upon individual desires, various color mixtures can be added to the concrete mixture. The color of the concrete mixture may be specifically selected to complement the overall design being implemented in the decorative pattern. It is contemplated that a variety of colors to enhance the effects of the decorative pattern may be employed by the present invention. In the present embodiment of the invention, the decorative pattern implemented on the concrete structure is similar to a red block. Therefore, the color of the cement mixture may be reflective of this block, taking the color of brown or dark brown or a mixture of colors complementing the desired aesthetic appeal of the decorative pattern. It is further contemplated that numerous colors may be employed at various stages of concrete preparation process to obtain varying shades of color if so desired.

After the concrete mixture has been poured, the same is preferably screeded to a desired level plane or grade. Screeding is leveling and smoothing the top layer of the concrete mixture, so the mixture is the same height as the forms, or guides, that surround it. The screeding of the concrete mixture results in the same defining a generally level or planar upper exposed surface. Therefore in order to facilitate the implementation of the decorative pattern, subsequent to screeding, the exposed surface of the concrete mixture is surfaced or finished with a conventional finishing tool to dispose a quantity of cement/fines paste derived from the concrete mixture at the exposed surface thereof.

A vibrating metal bull float may be utilized as the finishing tool. Such vibrating metal bull floats are known in the art and are characterized by possessing an extremely smooth or polished surface which, in addition to bringing up the appropriate amount of cement/fines paste for the subsequent manipulative steps of the present invention. It is contemplated that this initial finishing step may be completed through the use of a conventional bull float. A bull float consists of a trowel blade produced from a specially designed hollow section alloy extrusion with a convex profiled sole. Typically, the blade angle is easily controlled to facilitate forward and backward movement by a blade pitch control. A bull float generally provides very accurate levels without the need for guiding rails. In the present embodiment, it is preferred that either a vibrating magnesium bull float or a vibrating aluminum bull float is utilized.

According to one aspect of the present invention, when the exposed surface is in the plastic state, fine sand may be put over the exposed surface. The fine sand may comprise a color pigment. Further, it is contemplated that various combinations of color, texture, or other characteristics of the fine sand may be selected in order to complement the decorative pattern. In one embodiment, the fine sand function as a hardener and may be quartz sand.

It is contemplated that the present invention may be implemented upon a variety of concrete surfaces, including surface seeded exposed aggregate. Therefore, in an exemplary embodiment of the present invention, a quantity of aggregate may also be broadcast upon the exposed surface of the concrete mixture. When the exposed surface of the concrete mixture is still plastic, small size exposed aggregate is broadcast over the exposed surface. It is preferred that aggregates be clean, hard, strong particles free of absorbed chemicals or coatings of clay and other fine materials that could cause the deterioration of concrete. The selection of aggregates may impact the aesthetic appearance of the decorative pattern. In this regard, the aggregates are selected to complement the overall visual and textural characteristics of the design pattern.

As a result, a variety of techniques may be employed such that the aggregates carry the desired visual and textural characteristics as required by the decorative pattern. In an exemplary embodiment of the present invention, a benefaction process such as jigging or heavy media separation can be used to upgrade the quality of the aggregates. In this regard, once processed, the aggregates are handled and stored in a way that minimizes segregation and degradation and prevents contamination. Aggregates not only impact the aesthetic characteristics of concrete but also influence freshly mixed and hardened properties, mixture proportions, and economy of the concrete.

It is preferred that the aggregate comprise silica sand, glass bead, coarse sand, organic materials, metals, or composite materials. Additionally, it is preferred that any aggregate employed in the present invention be characterized by having a mean average diameter size of approximately one-eighth inch diameter, and further be characterized by possessing a generally rounded external surface configuration. Such small size aggregate is a substantial departure over prior art surface seeded exposed aggregates which typically comprise rock or gravel aggregate having average mean diameters of three-eighths of an inch or greater and are characterized by rough, jagged exterior surfaces. Typically, the aggregate is broadcast over the exposed surface of the concrete mixture by use of square point shovels and is applied at a preferred rate of approximately one pound per square foot of the exposed surface of the concrete mixture. It is preferred that the aggregate should not initially depress below the exposed surface of the concrete mixture, but rather should be broadcast solely to cover the same.

After being broadcast upon the exposed surface of the concrete mixture, the aggregate is mixed or worked into the exposed surface of the concrete mixture, and more particularly is mixed into the quantity of cement/fines paste at the exposed surface through the use of the above-described vibrating metal bull float. As indicated above, this vibrating metal bull float may comprise either a vibrating magnesium bull float or a vibrating aluminum bull float. This mixing of the aggregate with the cement/fines paste at the exposed surface derived during the previous vibrating metal bull float step is critical to the process of the present invention and insures that the aggregate is fully embedded into the cement/fines paste, and thus thoroughly adhered or bonded to the exposed surface of the concrete mixture upon resultant curing. In order to maintain the design pattern, it is critical that the aggregate is thoroughly bonded to the exposed surface so that individual pieces of aggregate are not dislodged and impacting the visual and textural effect of the decorative pattern.

Subsequent to the mixing of the aggregate into the cement/fines paste at the exposed surface of the concrete mixture, the exposed surface is finished with a decorative finishing mat to implement the decorative pattern upon the exposed surface. A decorative finishing mat is a concrete finishing mat that imprints a visual and textural decorative pattern upon the exposed surface of the concrete mixture. It is contemplated that the decorative finishing mat may be utilized upon any concrete surface.

A number of mats are used, and applied in juxtaposition to each other, so that the pattern is worked through the concrete surface in a progressive way. The procedure may be that a mat makes a pattern after pressing the mat to the surface of the concrete and another mat is positioned directly up to this mat, such as with an π

attachment configuration, and this mat is again pressed to the surface, whereafter the first mat is removed with the pattern imprinted into the surface. Then the whole pavement is made in such progressive steps. Accordingly, a number of mats are required in this method. Any textural pattern of the mats may be applied according to the present invention.

Subsequently, before impregnation liquid is applied, the surface may be washed to get rid of remaining material, such as powdered color and hardener.

As a final step, the impregnation liquid according to the invention is applied to the imprinted surface in an amount of for instance 125 ml per square meter surface. Preferably, the impregnation liquid is allowed to penetrate the surface in a passive manner, so that the upper part of the concrete foundation is saturated with impregnation liquid and the pores impregnated with the impregnation liquid.

In one embodiment of the invention, the impregnation liquid comprises silane and/or siloxane compounds. The silane compounds according to the invention has a size in the range of nanometers and the siloxane compounds may be slightly larger, but still in the nanometer size range. In one embodiment only silane compounds are used, and in another embodiment both silane and siloxane compounds are used in combination.

Useful silananes are alkyl alkoxy silane and useful siloxanes are organo polysiloxane. The composition of the impregnation liquid is known to a person skilled in the art.

In one embodiment of the invention, the impregnation liquid contains water as a carrier. However, also turpentine may be used as a carrier in certain other embodiments. The level of water or turpentine is known to a person skilled in the art.

In one embodiment of the invention, the impregnation liquid is not based on polyurethane or acrylate. It is necessary that polyurethane or acrylate are not used as the base material in the present invention. In one embodiment of the invention, a topical sealant, such as laquer, is not used.

In one embodiment of the invention, the impregnation liquid is applied to the concrete surface within two days after imprinting the concrete surface, such as within one day. To have the benefit of the method of the invention, it is important that the imprinted concrete surface is treated in a reasonably time after the surface has been imprinted. This may be important for the impregnation liquid to penetrate adequately into the upper foundation of the concrete material.

The resultant imprinted concrete surface exhibits an aesthetically appealing surface that conceals imperfections upon the surface and is advantageously suitable for high pedestrian traffic flooring applications. Additionally, the surface color and texture may be such that it approximates conventional flooring surfaces such as stone or wood. This resemblance can further be accentuated by saw cutting the concrete surface into rectangular grids to give the appearance that the individual rectangular squares of the grid were laid in a manner analogous to stone or wood flooring. Thus, the present invention comprises a significant improvement in the art by providing a surface seeded exposed aggregate concrete having a decorative pattern formed thereupon and possesses a surface texture and color having improved aesthetics over the prior art.

Additional modifications and improvements of the present invention may also be apparent to those of ordinary skill in the art. Thus, the particular combination of parts and steps described and illustrated herein is intended to represent only one embodiment of the present invention, and is not intended to serve as limitations of alternative devices and methods within the spirit and scope of the invention.

Claims (10)

A method of treating a concrete pavement with a visual and structural pattern, the method comprises the following steps: i) placing a cohesive concrete foundation using a wet concrete mix within a defined, pre-prepared area, the foundation having an upper part with an exposed concrete surface, ii) machining the wet concrete mix using machining tools to achieve a cohesive and substantially planar, exposed concrete surface, optionally allowing the wet concrete mixture to partially dry for a period thereafter, iii) adding a dye and a surface hardener to the concrete surface, iv) incorporating the dye and surface hardener into the upper part of the concrete foundation machining tools, possibly allowing the concrete mixture to partially dry for a period of time thereafter, v) adding one or more additional and different dyes and / or release agents to the surface, vi) embossing the concrete surface using a number of visual and structural pattern mats configured to face the concrete surface, the mats being pressed against the concrete surface partially into the upper part of the concrete foundation and thereby emboss a visual and structural pattern in the concrete surface, which resembles paving stones, and vii) finishing with a treatment of the embossed surface, characterized in that the dye substance in steps iii) to iv) are color pigments in powder form and that the treatment in step vii) is impregnation of the embossed surface with an impregnating liquid which penetrates the upper part of the concrete foundation comprising the surface hardener. The method of claim 1, wherein the impregnating liquid is distributed in the pores in the upper part of the concrete foundation comprising the surface hardener. The method of claim 1 or 2, wherein the impregnating liquid is applied to the concrete surface and is allowed to penetrate the upper part of the concrete foundation comprising the surface hardener in a passive manner. The method according to any one of the preceding claims, wherein a major part of the impregnating liquid used is distributed in the pores in the upper part of the concrete foundation such as more than 90% of the impregnating liquid used. The method according to any one of the preceding claims, wherein the amount of impregnating liquid used is more than 0.1 liters per square meters of concrete surface and / or less than 0.2 liters per. square meters of concrete surface. The method of any one of the preceding claims, wherein the impregnating liquid penetrates more than 0.5 cm into the upper part of the concrete foundation such as more than 1.0 cm. The method according to any one of the preceding claims, wherein the upper part of the concrete foundation comprising the surface hardener has a density of more than 15 times the density of such concrete, where a surface hardener is not added. The method of any one of the preceding claims, wherein the surface hardener comprises quartz mineral. The method according to any one of the preceding claims, wherein the impregnating liquid comprises silane and / or siloxane compounds. The method according to any one of the preceding claims, wherein a topical sealer such as lacquer is used.