BIODEGRADABLE OR DEGRADABLE FILM BAG FOR THE PLACEMENT OF CONCRETE OR FORMATION OF CONCRETE REPAIRS IN AND AROUND WATERCOURSES

Abstract

The invention relates to a bag used for the placement of concrete or grout, either hand placed or pump filled, in and around watercourses. The bags are impermeable and contained in nature, made of biodegradable, degradable or water soluble polymer film, typically made from renewable starch based polymers or water soluble polymers. The bags offer a means of easily and simply placing concrete or grout, safely, cleanly and without risk of contamination to the watercourse or environment from cement leakage, being impermeable in nature, whilst allowing the polymer film to safely degrade, dissolve or disintegrate, in the environment, without the risk of unsightly or environmentally detrimental polythene waste being placed in the watercourse.

Description

CROSS-REFERENCE TO APPLICATIONS

This Application claims the benefit of foreign priority under 35 USC §119 of GB Patent Application 0819163.7, filed Oct. 20, 2008, the entire content of which is hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates bags and, in particular, to a bag used for the placement of concrete or grout, either hand placed or pump filled, in and around watercourses.

BACKGROUND AND SUMMARY

There are many instances in which concrete needs to be placed in or around watercourses, for example, in order to repair or protect bridges from undermining or scour.

Simple, hand-placed, concrete filled hessian bags, similar to sand bags, have traditionally served this function, to enable the placement concrete in rivers for example, however, the open weave of the fabric allows the escape of cement fines into the water which can result in pollution. As a consequence, strict environmental legislation has resulted in their disfavour with environmental consulting bodies.

A range of other fabrics have been used to overcome these problems, utilising for example, a dense weave or coated fabrics, to provide an impermeable component to the fabric to better contain the concrete within the bag. These bags, due to their fabric nature, are typically sewn and in order to contain a sealed and impermeable nature have formal inlets and closure points, typically involving plastic components. As a result, this contained impermeable form of bagwork tends to be considerably more costly to manufacture than traditional hessian bags.

Another form of bag currently used, utilises paper. In this instance, bags containing dry sand/cement for example, can be placed in or around water. The sand/cement slowly absorbs external water through the paper bag to slowly cure the sand/cement mix, to form a hardened block. The potential for rips or tears and subsequent spillage of wet or dry material is however significant.

The invention described herein attempts to match the impermeable nature of coated fabric bags, instead utilising biodegradable or degradable polythene or polymer film, to form the bag lining. In this reference, polythene (adj) refers to any polymer that can be moulded when hot, and not just as an abbreviation of polyethylene. The biodegradable or degradable bag is typically made of corn or potato starch, or similar natural renewable polymer, a traditional fossil fuel polymer based film with additional catalysts that allow rapid physical degradation, or a water soluble polymer such as poly vinyl alcohol.

Biodegradable polymer film can also degrade rapidly, with the use of micro-organisms, with both biodegradable or degradable forms breaking down over a period of typically weeks to months, into carbon dioxide, water and methane. The ultimate result is that the polymer film and bagwork degrades and disappears, in a safe and non-polluting manner.

For the function of placing concrete in water, the use of biodegradable, degradable or watersoluble polymer film to form the bags has several advantages. Firstly, the impermeable nature of the polymer film means that unlike hessian, no cement fines can escape the bag, preventing cement pollution from escaping into the environment. The polymer film successfully achieves the primary role of containing the concrete and forming a concrete block, without allowing cement fines to escape out of the bag. Secondly, the use of polymer film means that seams can be glued or heat welded, eliminating the need for sewing for the bulk, if not all, of the bag that would typically be required for fabrics. Bags could therefore be mass-produced, using machines, significantly cheaper than sewn bags.

Finally, having a bag or “formwork” made from a material that breaks down in an environmentally safe manner means that within a relatively short period of time, all traces of the bag have disappeared, without looking tattered or unsightly and without causing adverse environmental impact or pollution. This is particularly true for starch-based polymer film, made from renewable natural resources, and water soluble forms of polymer film. It is important to appreciate the fact that bags used for the placement of concrete below water are permanent and remain in position after the blockwork has formed. Non-biodegradable polymer film, typically traditional oil based polythene, could conceivably be used for the bags, to place the concrete in an impermeable manner, however, the polythene would be unsightly and have a negative and very long term impact on any environment. Using renewable biodegradable polymer based polymer film, typically formed from corn, potato, tapioca or wheat starch, for example, or various forms of water soluble polymer, for example poly vinyl alcohol, will have many environmental benefits and importantly allow the use of polymer films in this application.

According to one aspect, a biodegradable or degradable film bag is described for the placement of concrete or formation of concrete repairs in and around watercourses. The bag is formed from a biodegradable or degradable polymer film forming a fully impermeable means of containment to allow concrete or grout to be placed safely in or around watercourses.

The biodegradable or degradable film bag can be specifically filled with said concrete or grout and then placed by hand in its intended final position. The film material can be made from corn, potato, tapioca, wheat or similar derived natural renewable polymer. The closure of the bag can be provided by sewing the top of the bag, Ziploc or similar means. The closure of the bag can be provided by a formal inlet, incorporating a push-in or threaded closure cap or plug. The film bag can be formed into extensive mattresses and pump filled with grout, concrete or similar cementitious material. The concrete or grout placed within the bags can be in its wet state or its dry or semi-dry state. The film bag can be placed within a simple hessian, jute or similar natural fabric bag, to give the appearance of a woven fabric bag. The polymer forming the film can be specifically a water soluble polymer.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the invention will now be described with reference to the accompanying drawings in which:

FIG. 1 shows a typical open-ended bag, in section and profile;

FIG. 2 shows the sequence of filling and closure;

FIG. 3 shows several options for closure; and

FIG. 4 shows how typically the bags are placed below water, in this instance to underpin an undermined wall or abutment.

DETAILED DESCRIPTION

The particular values and configurations discussed in these non-limiting examples can be varied and are cited merely to illustrate at least one embodiment of the present invention and are not intended to limit the scope of the invention.

FIG. 1 shows a biodegradable or degradable film bag, 1, in both front and side elevations, with the top end open but the opposing side, 2, sealed, in this instance with a heat weld. Gussets, 3, are formed along the sides, to allow expansion of the bag, when filled.

FIG. 2 shows a typical sequence of filling, showing an empty, open-ended film bag, 4, subsequently filled with concrete, 5, then sealed along the open end, in this example with a simple sewn line of stitching.

FIG. 3 shows possible forms of closure along the top edge. For bags with an open top edge, these include a simple sewn stitch line, 7, or a Ziploc closure, 8. Alternatively, a fully closed bag can be formed, including a formal inlet, 9, in this embodiment shown with a circular threaded closure that utilises a threaded closure cap or plug. For an embodiment incorporating a formal inlet of this nature, both ends of the bag are sealed, in this instance with a heat weld.

FIG. 4 shows how the hand placed bags are typically used and placed, once the bags are filled with concrete or grout, and closed in a manner shown in FIG. 3. the filled bags, 11, are placed, in this instance, to fill a void, 12, beneath an undermined bridge abutment, 13, below water.

The embodiments and examples set forth herein are presented to best explain the present invention and its practical application and to thereby enable those skilled in the art to make and utilize the invention. Those skilled in the art, however, will recognize that the foregoing description and examples have been presented for the purpose of illustration and example only.

Other variations and modifications of the present invention will be apparent to those of skill in the art, and it is the intent of the appended claims that such variations and modifications be covered.

The description as set forth is not intended to be exhaustive or to limit the scope of the invention. Many modifications and variations are possible in light of the above teaching without departing from the scope of the following claims. It is contemplated that the use of the present invention can involve components having different characteristics.

Claims

1. A biodegradable or degradable film bag for the placement of concrete or formation of concrete repairs in and around watercourses, where the bag is formed from a biodegradable or degradable polymer film forming a fully impermeable means of containment to allow concrete or grout to be placed safely in or around watercourses.

2. A biodegradable or degradable film bag for the placement of concrete or formation of concrete repairs in and around watercourses, as claimed in claim 1, where the bags are specifically filled with said concrete or grout and then placed by hand in its intended final position.

3. A biodegradable or degradable film bag for the placement of concrete or formation of concrete repairs in and around watercourses, as claimed in claim 1, where the film material is made from corn, potato, tapioca, wheat or similar derived natural renewable polymer.

4. A biodegradable or degradable film bag for the placement of concrete or formation of concrete repairs in and around watercourses, as claimed in claims 2, where the film material is made from corn, potato, tapioca, wheat or similar derived natural renewable polymer.

5. A biodegradable or degradable film bag for the placement of concrete or formation of concrete repairs in and around watercourses, as claimed in claim 1, where closure of the bag is provided by sewing the top of the bag, Ziploc or similar means.

6. A biodegradable or degradable film bag for the placement of concrete or formation of concrete repairs in and around watercourses, as claimed in claim 2, where closure of the bag is provided by sewing the top of the bag, Ziploc or similar means.

7. A biodegradable or degradable film bag for the placement of concrete or formation of concrete repairs in and around watercourses, as claimed in claim 1, where closure of the bag is provided by a formal inlet, incorporating a push-in or threaded closure cap or plug.

8. A biodegradable or degradable film bag for the placement of concrete or formation of concrete repairs in and around watercourses, as claimed in claim 2, where closure of the bag is provided by a formal inlet, incorporating a push-in or threaded closure cap or plug.

9. A biodegradable or degradable film bag for the placement of concrete or formation of concrete repairs in and around watercourses, as claimed in claim 1, where the film bag is formed into extensive mattresses and pump filled with grout, concrete or similar cementitious material.

10. A biodegradable or degradable film bag for the placement of concrete or formation of concrete repairs in and around watercourses, as claimed in claim 1, where the concrete or grout placed within the bags is in its wet state.

11. A biodegradable or degradable film bag for the placement of concrete or formation of concrete repairs in and around watercourses, as claimed in claim 2, where the concrete or grout placed within the bags is in its wet state.

12. A biodegradable or degradable film bag for the placement of concrete or formation of concrete repairs in and around watercourses, as claimed in claim 1, where the concrete or grout placed within the bags is in its dry or semi-dry state.

13. A biodegradable or degradable film bag for the placement of concrete or formation of concrete repairs in and around watercourses, as claimed in claim 2, where the concrete or grout placed within the bags is in its dry or semi-dry state.

14. A biodegradable or degradable film bag for the placement of concrete or formation of concrete repairs in and around watercourses, as claimed in claim 1, whereby the film bag can be placed within a simple hessian, jute or similar natural fabric bag, to give the appearance of a woven fabric bag.

15. A biodegradable or degradable film bag for the placement of concrete or formation of concrete repairs in and around watercourses, as claimed in claim 2, whereby the film bag can be placed within a simple hessian, jute or similar natural fabric bag, to give the appearance of a woven fabric bag.

16. A biodegradable or degradable film bag for the placement of concrete or formation of concrete repairs in and around watercourses, as claimed in claim 1, whereby the polymer forming the film is specifically a water soluble polymer.

17. A biodegradable or degradable film bag for the placement of concrete or formation of concrete repairs in and around watercourses, as claimed in claim 2, whereby the polymer forming the film is specifically a water soluble polymer.