GB2575231A

GB2575231A - Improved Bermuda roof tile

Info

Publication number: GB2575231A
Application number: GB1806303.2A
Authority: GB
Inventors: Mason Philip
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-04-18
Filing date: 2018-04-18
Publication date: 2020-01-08
Anticipated expiration: 2038-04-18
Also published as: GB201806303D0; GB2575231B

Abstract

There is disclosed a mix and method for manufacturing cementitious roofing tiles which resemble traditional Bermuda "slate" tiles. The mix comprises crushed glass making up 15% to 60% of the total composition weight; a hydraulic cement binder; a fine aggregate sand; another aggregate selected from limestone, scoria, perlite, vermiculite, hemp, expanded shale and slate; and an alkali-silica reaction suppressant.

Description

FIELD OF THE INVENTION

A mix and method for making roofing tiles using post-consumer glass and other aggregates, and cement to bind the mix and a hydraulic press to form the tiie.

BACKGROUND OF THE INVENTION

The traditional method of building a Bermuda ‘slate roof for the last 400 years has been to use quarried natural limestone ties that measure 18” x 12 x 1“ thick (Traditional Tile). These Traditional Tiles are overlapped and bedded in mortar and rest on top of permanent timber roof framing. The roof is considered a ballast type construction relying primarily on the dead weight of the stone and mortar to keep from lifting off in high winds (e.g. hurricanes). However, in recent years major hurricanes (Category 3 and above) have become more frequent and severe with several storms causing extensive roof damage island wide. Hurricane damage creates an immediate demand for replacement Traditional Tiles to repair the damage to roofs in order to make them weather tight. Unfortunately, Bermuda’s quarrying capacity is limited and quarries cannot meet this immediate demand for Traditional Tiles, resulting in long delays to roof repairs. Also the opening of new quarry sites is restricted due to a growing desire to protect environmentally sensitive land.

Currently there are a number of solutions tor replacing the locally quarried Traditional Tiles with a manufactured roofing product. Some of these solutions attempt to provide a suitable substitute roofing tile product, but these solutions fail to meet the needs of the industry because they do not match the physical characteristics of Traditional Tile. Imported aerated autoclaved concrete (AAC) slate products of similar size are half the weight of Traditional Tile requiring them to be mechanically fastened to the wood framing with clips in order to attain sufficient resistance to wind uplift forces. Imported AAC roofing tile does not use any locally available recycled materials and exhibits thermal and moisture absorption characteristics that results in recurring cracks in the finished roof. Tradesmen laying AAC roofing tile must adjust mortar mix and laying down techniques to account for the increase rate of water absorption from AAC rooting tile resulting in a noticeable deviation from traditional practices of laying quarried limestone roofing tile. Other solutions attempt to manufacture a roofing tile product using traditional wet-mix flowable concrete but this solution is similarly unable to meet the needs of the industry because the flowable concrete mix slurry must be placed into individual molds and cured tor up to seven days before de-molding. Also this finished concrete product is denser and requires more effort to cut and shape individual pieces. The characteristics of a wet-mix concrete molded roofing tile do not closely resemble that of the Traditional Tile resulting in rejection by local tradesmen as an inferior roofing tile that deviates too far from the traditional quarried limestone roofing tile product.

It would be desirable to have a locally manufactured roofing tile product that is made from up to 70% recycled materials included post-consumer glass (recycled glass, hereinafter referred to as RG) and that can be stockpiled in large quantities without deteriorating and stacked to reduce inventoried storage space. This would ensure sufficient quantities are available during peak demand periods such as post hurricane repairs to existing Traditional Tile roofs. Furthermore, it would also be desirable to have a manufactured roofing tile that is the exact same size and weight as the Traditional Tiie product but is stronger and more durable to reduce breakage during transportaticn and handling. Still further, it would be desirable to have a roofing tile that exhibits characteristics similar to Traditional Tile that tradesmen find desirable when handling, cutting and laying the tiie on timber framed roofs. Still further, it would be desirable to have a roofing tile that has low thermal expansion and tow moisture absorption characteristics in order to reduce cracking and the associated regular repairs to cracks in stone tile roofs. Still further, it would be desirable to have a roofing tile that enables it to be mechanically fastened to the underlying timber framing in order to improve resistance to uplift and roof damage during severe high winds. Still further it would be desirable protect Bermuda’s natural environment by reducing Bermuda’s dependence on quarrying natural stone for use as a roofing tile. Therefore, there currently exists a need in the industry for a Bermuda manufactured roofing tile that is a better substitute to match Traditional Tiles and uses up to 70% locally available recycled materials in its composition.

SUMMARY OF THE INVENTION

Disclosed is a mix design and method for manufacturing a roofing tile using up to 70% locally available materials and is a superior replacement for Traditional Tiles. This manufactured roofing tile is made up of the following components, a hydraulic cement binder, RG, a light weight aggregate, a fine aggregate, an alkalai-silici reaction (ASR) suppressant and water. These components are connected as follows: the optimum proportions of components are measured by weight and mechanically blended together as a dry cementitious composition. A small quantity of clean water is added to the dr/ mix composition in an amount only necessary to achieve optimum moisture content for compaction and to effect hydraulic setting of the cementitious composition, without adding any additional free water to the mix. A removable base plate sits at the bottom of the molding frame ready to receive a charge of damp mix material. The damp mix is loaded into the mold frame which is sized and shaped to achieve the desired finished shape of the roofing tile product after compaction. A hydraulic ram press applies compactive force within the mold confines for a predetermined length of time. The compactive force is then removed and the mold frame is lifted free from the compacted tile product. The tile product and base plate is removed from the work area and allowed to cure in an environment with 90% relative humidity until it reaches sufficient strength to safely handle without breakage. The roof tiles are then removed from the reusable base plate and stored on edge until full strength is achieved. The finished roofing tile is then bundled in groups and stacked three high on edge on wood pallets ready for transporting to the construction site.

The mix design and method may also have one or more of the following variations: other light weight aggregate may be substituted for perlite, specifically vermiculite, hemp, expanded clay, shale, and slate; industrial waste by-products, such as fly ash, expanded slag cinder, and bed ash. Proportions of component aggregates may be varied provided the finished dry weight of the roofing tile falls between a minimum value of 8ibs and a maximum value of 10ibs and exhibits the same desirable strength, durability, handling and working characteristics of the optimum mix ratios described herein. A variety of commonly known pozzolans may be used as aikali-silica reaction suppressant substitutes for fly ash. consisting of pumice, calcined clay, calcined shale, metakaolin, slag and silica fume. A sma I quantity of sodium bentonite may be added io improve molding characteristics and reduce wastage during molding, de-molding and handling. Micro-synthetic fibres may be added to the mix design to improve strength and resistance to cracking. The roofing tile product may be molded with one or two slotted anchorage holes of 3/16 diameter to facilitate mechanically fixing the slate to the wood framing with industry standard wood screws and large diameter plastic washers without having to drill through the tiie.

The disclosed manufactured roofing tile is unique when compared with other known roofing tile products and solutions because it: (1) uses locally available recycled components including RG in the design mix, reducing the need for costly imported materials (2) produces a superior roofing tile product that is stronger and more durable than Traditional Tils resulting in less wastage during storage, transportation and handling (3) can be palletized and stacked higher for long term emergency inventories without any deterioration in quality, (4) can be manufactured in climate controlled indoor facilities 24 hours a day, 7 days a week unlike Traditional Tile which is weather dependent.

Among other things, it is an object of the present invention to provide a method and mix design for making a cementitious roofing product o* specific size and weight using post-consumer glass and other aggregate that produces a roofing tile product that does not suffer from any of the problems or deficiencies associated with previous solutions.

The disclosed manufactured roofing tile is unique in that it is structurally different from other known roofing tiles or solutions. More specifically, the roofing tile is unique due to the presence of: (1) RG and other components in the mix design in a proportion and grading that achieves the most desirable characteristics of a roofing tile substitute for Traditional Tile; (2) can be molded with only the optimum level of moisture for a damp mix design to achieve compaction allowing for immediate release from the mold; and (3) can be molded with pre-formed slotted screw holes to allow the option of securing the tile to the wood framing with wood screws for additional uplift resistance during severe windstorms (4) is strong and durable enabling it to be palletized and stacked to reduce storage space (5) is the exact same weight and size of Traditional Tile enabling a true like-for-iike substitute for Traditional Tile with no deviation from accepted local practice in building and finishing a stone tile roof covering.

It is an object of this invention to provide a method of manufacturing a superior roofing tile using local labor and equipment reducing the delays and costs of importing roofing tiles. Further still it is an object of this invention to provide a way to manufacture roofing tile that is stronger, more durable and more economical than other locally available solutions Still further it is an object of this invention to utilize stockpiles of locally available RG in the mix design promoting a green’¹environmentally positive product from waste material.

The invention will now be described more fully hereinafter with reference to the accompanying drawings, which are intended to be read in conjunction with both this summary, the detailed description and any preferred and/or particular embodiments and variations specifically discussed or otherwise disclosed. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of illustration only and so that this disclosure will be thorough, complete and fully conveys the full scope of the invention to those skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. #1 The sequence of operation for making a roofing tile comprising of the following steps:

A. the biended damp mix (3) is placed into a mold frame (1) and on top of a removable base plate (2)

B. the damp loose mix is leveled to the top of the mold frame

C. a hydraulic ram (4) is lowered onto the loose damp mix and compactive force is applied

D. the compactive force is removed and the hydraulic ram and mold frame are lifted clear of the compacted shape and base plate

E. the compacted mix and base plate are moved to a curing room to strengthen the tile in an environment maintained at room temperature and 90% relative humidity until sufficient strength has been achieve to safely handle the roofing tile without damage

F. the cured roofing tile (6) molded with or without anchorage holes (5) is separated from the reusable base plate, stacked and stored on edge ready fortransporting.

BRIEF DESCRIPTION OF THE INVENTION

The present invention is directed to a method and mix design for making a cementitious roofing product of specific size and weight using RG and other aggregate.

In its most complete version the optimum mix design to achieve a desirable manufactured roofng tile product is formulated from the following components proportioned by weight; 15-60% RG (also known as cullet) with washed particle sizes equally distributed from fine dust to % inch sieve size, 20-25%fme aggregate sand, 12-20% perlite with cumulative particle size of 40-65% by weight passing thorough #16 mesh-sieve, 10-20% Portland cement Type 2, 2-5% fly ash (Type C) and 1% clean water. These components are connected as follows; the dry components, being all of the listed components above save for the water, are mechanically blended together thoroughly and fresh water >s slowly added until a homogenous damp mix is achieved that exhibits an optimum moisture content with no excess free water. Optimal moisture content being achieved when the majority of the damp mix stays clumped together in a ball when compressed in the hand. No additional free water should be added after this stage. The damp homogenous mix is loosely transferred to molds sized and proportioned to achieve the desired final roofing tile dimensions of 16“ x 12 x 1” after compactive force is applied. Hydraulic rams are lowered into the loose homogenous damp mix within the mold frame and compactive force is applied for a defined period of time sufficient to achieve the desired finished roofing tile density and strength characteristics The compactive force is then removed and the ram raised allowing the mold frame to lifted clear of the molded roofing tile and base plate. The molded tile and temporary base plate is carefully moved away from the work area and allowed to cure in an environment of 90% relative humidity until the tile has reached sufficient strength to be manhandled and removed from its base plate without damaging the tile The roofing tile product in then stored on edge for a further period of time until it has achieved full strength at which time it is bundled and wrapped with other roofing tiles and pelletized ready for transporting to construction sites or stored for long term emergency use. According to the invention.

[claims commence on following page]

Claims

A method and composition for a cementitious roofing tile, traditionally measuring!8” x 12” x 1”, comprising:

a hydraulic cement;

a fine aggregate;

a light weight aggregate;

post-consumer crushed glass (recycled glass, “RG”) an alkali-silica reaction (ASR) suppressant;

and water wherein the average particle size of the fine aggregate and light weight aggregate varies from 1 micron a maximum size of 2mm and the average particle size of the RG ranges from size 1 micron to a maximum of 5mm; and wherein the weight ratio of water to dry mix composition is in the range of 15 - 20% and is just sufficient to affect hydraulic setting of the composition with no additional free water.
2. A method and composition for a cementitious roofing tile of claim 1, wherein the fine aggregate is sand with an average particle size of 1 mm or less.
3. .A method and composition for a cementitious roofing tile of claim 1, which has a weight percentage of the fine aggregate sand material ranges from 20-25% relative to the total weight of the composition.
4. A method and composition for a cementitious roofing tile of claim 1, which has a weight percentage of hydraulic cement ranges from 10 - 20% relative to the total weight of the composition.
5. A method and composition for a cementitious roofing tile of claim 1, wherein the light weight aggregate is at least one selected from the group comprising of limestone, perlite, expanded shale or slate, hemp, vermiculite and scoria.
6. A method and composition for a cementitious roofing tile of claim 1, which has a weight percentage of the light weight aggregate ranging from 12 - 20% relative to the total weight of the composition.
7 A method and composition for a cementitious roofing tile of claim 1, wherein the crushed recycled glass having an average particle size in the range Of 1 micron to 5mm.
8. A method and composition for a cementitious roofing tile of claim 1, which has a weight percentage of recycled glass ranging from 15-60% relative to the total weight of the composition.
9. A method and composition for a cementitious roofing tile of claim 1, wherein the alkalisilica reaction (ASR) suppressant or pozzoianis at least one selected from the group consisting of natural pumice, fly ash, silca fume, blast furnace slag, volcanic ash or metakaoiin.
10. A method for manufacturing a cementitious roofing tile, the method comprising:

measuring a predetermined amount by weight percentage of dry components, the dry components being, a fine aggregate sand, an aggregate, a crushed glass and an alkali-silica reaction (ASR) suppressant;

mechanically blending the dry components to form a homogenous dry composition mixture; adding a volume of water to the homogeneous dry composition mixture , forming a damp concrete mixture; placing the damp concrete mixture in a predetermined sized molding frame, the molding frame having a removable base plate; and applying a compactive vibratory force to the damp concrete mixture within the molding frame to achieve a desired finished shape; removing the compacted tile from the molding frame and transporting the compacted tile to a controlled environment for curing until a desired strength associated with the compacted tile has been established for safe handling and transportation to construction sites;

wherein the aggregate is selected from one of perlite, vermiculite, hemp, expanded clay, shale and slate..

10, A method and composition for a cementitious roofing tiie of ciaim 1, which has a weight percentage of ASR ranging from 0-15% relative to the total weight of the composition.

11, A method and composition for a cementitious roofing tile of claim 1, wherein an additive to improve mold forming characteristics may include sodium bentonite at a weight percentage of 0.5 - 1.5% relative to the total weight of the composition.

12, A method and composition for a cementitious roofing tile of claim 1, which has a 28day dry unit weight in the range of 1050 - 1350 kg/m3 after setting.

13. A method and composition for a cementitious roo mg tile of claim 1, which has a minimum 28day compressive strength in the range of 2 5 MPa after setting.

14. A method and composition for a cementitious roofing tile of claim 1, where predetermined slotted anchorage holes are formed at one end of the tile to accommodate screw fixing to underlying timber roof framing during roof installation if desired

15. A method and composition for a cementitious roofing tiie of claim 1, where microsynthetic fibers may be a composition strength and resistance to cracking.

18. A method and composition for a cementitious roofing tile of claim 1, the method comprising:

mixing the cement, the fine aggregate, the light weight aggregate, the recycled glass and the ASR suppressant to form a homogenous dry composition mixture; adding just enough water to the cement composition mixture to affect hydraulic setting to achieve optimum moisture content without any free water, forming a damp concrete mixture; placing the damp concrete mixture in a predetermined sized molding frame and applying a compactive vibratory force to achieve the desired finished shape. Immediate de-molding of the compacted tile from the surrounding mold frame and transporting the tile to a controlled environment curing room until sufficient strength has been established for safe handling and transportation to construction sites.

As discussed, the invention has many different features, variations and multiple different embodiments. The invention has been described in this application at times in terms of specific embodiments for illustrative purposes and without the intent to iimit or suggest that the invention conceived is only one particular embodiment. It is to be understood that the invention is not limited to any single specific embodiments or enumerated variations. Many modifications, variations and other embodiments of the invention will come to mind of those skilled in the art to which this invention pertains, including but not limited to the size of roofing tile produced, and which are intended to be and are covered by both this disclosure. It is indeed intended that the scope of the invention should be determined by proper interpretation and construction of the disclosure, including equivalents, as understood by those of skill in the art relying upon the complete disclosure at the time of filing.

05 03 19

Amendments to the claims have been follows

Claims:

1. A composition for a cementitious roofing tile, the composition comprising:

a hydraulic cement binder making up 10% to 20% of a total composition weight;

a fine aggregate sand making up 20% to 25% of the total composition weight;

an aggregate making up 12% to 20% of the total composition weight;

a crushed glass making up 15% to 60% of the total composition weight;

an alkali-silica reaction (ASR) suppressant;

and water;

wherein the aggregate is selected from one of perlite, vermiculite, hemp, expanded clay, shale and slate; and wherein the average particle size of the fine aggregate sand and the aggregate varies from 1 micron to a maximum size of 2mm and the average particle size of the crushed glass ranges from size 1 micron to a maximum of 5mm.

2. The composition of claim 1, wherein the fine aggregate has an average particle size of 1mm or less.

3. The composition of claim 1, wherein the alkali-silica reaction (ASR) suppressant is at least one selected from the group consisting of natural pumice, fly ash, silca fume, blast furnace slag, volcanic ash or metakaolin.

4. The composition of claim 1, wherein the alkali-silica reaction (ASR) suppressant makes up 0% to 15% of the total composition weight.

5. The composition of claim 1, further comprising an additive composed of sodium bentonite making up 0.5% to 1.5% of the total composition weight.

6. The composition of claim 1, which has a 28 day dry unit weight in the range of 1050 1350 kg/m3 after setting.

7. The composition of claim 1, wherein the cementitious roofing tile has a minimum 28 day compressive strength in the range of 2 - 5 MPa after setting.

8.

The composition of claim 1, wherein the cementitious roofing tile further comprises:

05 03 19 a body measuring 18” x 12 “ x 1” (45.7cm x 30.4cm x 2.5cm) and having one or more predetermined slotted anchorage holes formed at one end of the tile to accommodate screw fixing to underlying timber roof framing during roof installation.

9. The composition of claim 1, further comprising micro synthetic fibers configured to increase composition strength and resistance to cracking.