Surface covering mats are often comprised of stone, brick, plastic, or concrete that are arranged to form a covering over a surface. These surface covering mats may be utilized for many reasons including as a surface for walking, for vehicular traffic, as a decorative element or as a protective surface. Surface covering mats that are predominately concrete or other rigid materials are generally not flexible, are difficult to install, or are unable to articulate over uneven surfaces, particularly on slopes. Terrain on a development site often includes hills and slopes that may be constructed of relatively stable or stabilized engineered soil that requires additional protection from elements such as wind, rain, and snow to stay in place over time and with little added maintenance. Conventional protective applications for these uneven surfaces are generally difficult and/or expensive to install, aesthetically unpleasing or difficult to maintain. Conventional methods typically utilize plants and grasses, hand placed natural stone, manufactured block, mechanically placed block or a mechanically sprayed-on concrete shell such as gunite.
Utilizing plants and grasses in conjunction with surface coverings on slopes is sometimes aesthetically desirable. Additionally, the roots of plants help to protect the surface by holding it together. Depending on site conditions and geographic regions, plants are difficult to grow and maintain due to location, cold, heat, lack of moisture or other conditions.
When utilizing hand placed natural stone, every stone is a different shape size and thickness requiring them to be handled individually. Each stone must be carefully fitted together and embedded into the soil to help prevent it from sliding or rolling and also to achieve the desired visual aesthetic in the exposed surface. Hand placed stonework is slow to install and also generally requires the installer to be a skilled craftsman with knowledge of stone cutting, fitting and placement. For these and other reasons, hand placing stone is generally known to be difficult and slow, especially on slopes, making the work expensive.
When manufactured blocks are used, they are normally used as ballast over geogrid to hold it in place. Geogrids, used widely in Civil Engineering applications to provide tensile reinforcement of soil, are geosynthetic materials made from polymers such as polypropylene, polyethylene or polyester which are formed as an open grid that allow soil to strike through the apertures allowing the two materials to interlock together to give a composite behavior. In a typical installation, geogrid is first applied directly over the slopes and then covered with protective ballasting elements such as gravel, stone or blocks. On slopes, gravel has limited appeal unless the grid contains large holding pockets to contain the gravel, making the grid expensive. Additionally, these installations are sometimes considered unsightly and difficult to install. Stone is rarely used because of its irregular nature. Manufactured block requires that each block be hand placed or, if mechanical installation is used, the blocks need to be cabled together prior to installation. This requires the block to first be individually placed on a flat surface then cabled together into large mats. These mats then must be moved to the area of installation by using a crane to lift the mats onto flatbed trucks for transport to the installation site where another crane must lift the mats into position. These mats are large and their final cabled shapes require them to be pre-engineered to fit specific places on the site.
When gunite is used, a wire or plastic mesh is applied over the slope and then concrete is sprayed over the mesh, providing a thin yet solid surface covering held together by the mesh. The process is fast, and compared to other methods, comparably inexpensive. However, the visual appearance of gunite is not usually desirable. Further, since application of gunite results in a solid shell over the surface, sometimes erosion may happen in the soil beneath the gunite covering which cannot be seen from the surface. This is a problem because if the erosion beneath the shell removes soil, the gunite can crack or collapse which leaves the slope unsightly, potentially dangerous and expensive to repair.
SUMMARY In accordance with the present invention, an articulating composite surface covering mat includes multiple units having a natural or irregular appearance and formed of a filler, each having an irregular peripheral shape and a flexible geogrid extending between and through the units. Irregular gaps are formed between the multiple units and have irregular spacing as measured horizontally at the geogrid. A peripheral surface of the mat is defined by segments of peripheral surfaces of at least some of the multiple units. The peripheral surface of the mat has at least three sides, at least two sides including the segments of the peripheral surfaces of the multiple units defining S-curve geometry. At least two of the three sides of the mat has a center point, and a first segment of the side is a 180-rotation of a second segment of the side about the center point.
A process for the formation of an articulating composite surface covering mat that includes spaced apart units that are held together by a geogrid includes the step of disposing a bottom mold on a substantially level surface, where the bottom mold has a generally planar bottom surface that defines the top surface of the formed mat, and the where the bottom mold has transverse walls extending from the bottom surface. Additional steps include locating a geogrid onto at least one cavity that is defined by the bottom mold or a top mold or a combination of both the bottom and the top molds, such that the geogrid is generally horizontal, where the geogrid extends into each of the spaced apart units to be formed. Another step includes placing the top mold over the bottom mold to form the mold assembly, where the bottom mold and the top mold define the cavity therebetween for receiving the geogrid, and where the top mold has a generally planar top surface and transverse walls extending therefrom. A further step includes sealingly engaging at least a portion of the transverse walls of the top mold with corresponding transverse walls of the bottom mold at a location of no geogrid therebetween, and adding a filler to the mold assembly through openings in the top mold.
A process for the formation of multiple articulating composite surface covering mats, where each mat includes spaced apart units that are held together by a geogrid and define a mat peripheral surface, includes the steps of disposing a bottom mold on a substantially level surface, where the bottom mold has a generally planar bottom surface that defines the top surface of the formed mat, and transverse walls extending from the bottom surface of the bottom mold. A first portion of the transverse walls in the bottom mold define the spaced apart units to be formed, and a second portion of the transverse walls in the bottom mold define the mat peripheral surfaces of the multiple mats to be formed. Further steps include locating a geogrid horizontally onto at least one cavity defined by the bottom mold or the top mold or a combination of both the bottom and top molds, where the geogrid extends over the first portion of transverse walls defining the spaced apart units and into each of the spaced apart units within each of the multiple mats, but where the geogrid does not extend over the second portion of the transverse walls defining the peripheral surfaces of the multiple mats to be formed. Additional steps include placing the top mold over the bottom mold to form the mold assembly, where the bottom mold and the top mold define the cavity therebetween for receiving the geogrid, and where the top mold has a generally planar top surface and transverse walls extending therefrom. More steps include engaging the transverse walls of the top mold with the second portion of transverse walls of the bottom mold at the peripheral surface of the multiple mats to be formed, and adding the filler to the mold assembly at an opening in the generally planar top surface of the top mold.
A process for the formation of differently shaped articulating composite surface covering mats which each comprise spaced apart units that are held together by a geogrid is also provided. The process includes providing multiple mold assemblies that each define differently shaped spaced apart units, where the mold assemblies have a top mold and a bottom mold each having transverse walls that include cavity walls and sealing walls. The process also includes placing a universal geogrid having positive space and negative space into one of the multiple mold assemblies, where the universal geogrid is received in one of the multiple mold assemblies such that the positive space of the universal geogrid is received in a cavity defined between the cavity walls of at least one of the top mold and the bottom mold, and the negative space of the universal geogrid at least one of located at the engagement of the sealing walls of the top mold and the bottom mold. Further, the universal geogrid is receivable into at least two of the multiple mold assemblies that define differently shaped spaced apart units such that the positive space of the universal geogrid is received in the cavity defined between the cavity walls of at least one of the top mold and the bottom mold, and the negative space of the universal geogrid is located at the engagement of the sealing walls of the top mold and the bottom mold.