Patent Application
20070204548
This invention is related to the field of building construction and more specifically to a new building material and building blocks.
In 1981, Louis Gagné built his first straw bales and mortar house. The objective was an affordable house which was well insulated, structurally sound, simple and easy to build. Louis Gagné received a CMHC grant to test this wall system, and published the results in the following report: GAGÉ, Louis, A Straw Bales And Mortar House Demonstration Project, CMHC, Ottawa, Canada, 1986. This report reveals the exceptional fire resistance, the structural soundness and the insulation value of this straw bales and mortar building method. It is generally known that straw is a hollow stem derived from agriculturally produced cereals, which is traditionally used for bedding in stables, thatching, stuffing, insulating, etc. Furthermore, straw is commonly available in the form of bales. In the following years, Louis Gagné went on building with straw bales, using concrete for the structure instead of mortar, perfecting the techniques used to erect the walls, refining the process and the results. In spite of these improvements, building with straw bales and concrete remains a method with limited commercial value, because it is a labour intensive process where individuals build singles houses, and where standards are hard to define since the bales from the field escape control as to size and density.
In the last few years, Louis Gagné stopped building with straw bales and concrete because the development of this building approach seems to have reached its full potential.
Accordingly, an improved building material and building method is highly desirable.
One aspect of the present invention provides a building material made of chopped straw mixed with Portland cement, mortar cement or lime and a polymer emulsion diluted in water which acts as the bonding agent.
In another aspect of the present invention, the resulting material is compressed into blocks of different sizes and shapes.
In another aspect of the present invention, the proportion and the combination of the elements (chopped straw, Portland cement, mortar cement or lime and polymer emulsion diluted in water) as well as the pressure exerted to make the blocks, can be modified to increase or decrease the density of the blocks.
In still another aspect of the present invention, the chopped straw (mainly cereal straw such as wheat, rye, barley, oats and rice where available) of ideal lengths comprise between 5 cm and 10 cm substantially (the straw lengths can be shorter or longer) is the filler element and represents the bulk of the block's volume. The cement surrounding each piece of straw gives it rigidity and strength. The gluing factor and the adherence of the cement to the pieces of straw is provided by a polymer emulsion diluted and water.
In yet another aspect of the present invention, this solution can be also mixed with mortar cement or lime or both in order to provide a better adherence of the cement to the pieces of straw.
In still another aspect of the present invention, while straw constitute the bulk of the volume of the building material, the proportion of straw, Portland cement, mortar cement or lime and the polymer emulsion diluted in water is one of the factors which determine the density of the blocks. Therefore, if the amount of cement is augmented in the mix, the density of the block will increase, and hence its structural value will also be increased. If the mix is made to be lighter by increasing the proportion of straw and using less cement, the blocks will have less structural value but a higher insulating value.
In another aspect of the present invention, the density of the blocks will vary with the compression force used to make the blocks. Increasing the pressure to form a block will increase its density and its structural value. Diminishing the pressure to form a block will reduce its structural value while increasing its insulating factor.
In another aspect of the present invention, the sizes of the blocks can be changed to suit different building needs. If the width of the block is increased, the structural value and the insulating factor are increased, and a larger volume of concrete could also be poured to increase the structural strength of the wall. If the length and the height of the block is increased it will take less time and fewer blocks to build a wall.
In another aspect of the present invention, the shapes of the blocks are designed to fit together as a four interlocking blocks system, in which a first block is shaped with a horizontal groove on top, a flat bottom, a vertical groove on one side and a vertical tongue on the opposite side; a second block shaped with an horizontal groove on top, a flat bottom and a vertical groove on each side; a third block shaped with an horizontal groove on top, an horizontal tongue on the bottom, a vertical groove on one side and a vertical tongue on the opposite side; and a fourth block shaped with an horizontal groove on top, an horizontal tongue on the bottom and a vertical groove on each side are used either to build a wall directly by interlocking the blocks together or to build a wall with a concrete structure by setting together the vertical and horizontal grooves at chosen intervals which can be filled with concrete that can be reinforced or not with steel rods.
In another aspect of the present invention, the surfaces of the wall can be finished by applying directly coats of mortar, stucco or plaster on those surfaces depending on the building requirements.
One broad aspect of the present invention provides a building material for the construction of building blocks, the building material comprising: chopped straw; Portland cement; mortar cement or lime; and a bonding agent comprising a polymer emulsion, wherein the straw is chopped in lengths substantially between 50 mm and 100 mm.
In some embodiments, the straw comprises the bulk of the volume of the building material.
In some embodiments, the straw comprises cereal straw.
In some embodiments, the cereal straw is selected from the group of wheat, rye, barley, oats and rice.
In some embodiments, the bonding agent further comprises at least one of: mortar cement and lime.
Other embodiments provide a building block formed of the building material, the building block having a generally solid rectangular exterior configuration.
In other embodiments the building block comprises a front face; a rear face opposite the front face; a top surface adjacent to the front face and the rear face, the top surface having a horizontal groove substantially parallel to the front face; a bottom surface adjacent to the front face and the rear face, and opposite the top surface; a first end face adjacent to: the front face; the rear face; the top surface; and the bottom surface, the first end face having a vertical groove substantially parallel to the front face; and a second end face adjacent to: the front face; the rear face; the top surface; and the bottom surface, the second end facing being opposite the first end face.
In some embodiments, the second end face has a vertical groove, substantially parallel to the front face.
In other embodiments, the second end face has a vertical tongue, substantially parallel to the front face, the vertical tongue configured to mate with a corresponding vertical groove of an adjacent similar building block.
In some embodiments, the bottom surface is substantially flat.
In other embodiments, the bottom surface has a horizontal tongue substantially parallel to the front face, the horizontal tongue configured to mate with a corresponding horizontal groove of an adjacent similar building block below.
Another embodiment of the present invention provides a building block system comprising a plurality of building blocks, the building blocks selected from one or more of: a first block having a horizontal groove on a top surface, a flat bottom surface, a first end face having a vertical groove and a second end face having a vertical groove; a second block having a horizontal groove on a top surface, a flat bottom surface, a first end face having a vertical groove and a second end face having a vertical tongue; a third block having a horizontal groove on a top surface, a horizontal tongue on a bottom surface, a first end face having a vertical groove and a second end face having a vertical groove; a fourth block having a horizontal groove on a top surface, a horizontal tongue on a bottom surface, a first end face having a vertical groove and a second end face having a vertical tongue, the system permitting building of a wall by stacking courses of blocks selected from the first block, second block, third block and fourth block such that blocks can be selected to mate vertical tongues with corresponding vertical grooves or to arrange facing vertical grooves of adjacent blocks to allow for filling the resulting vertical cavity with reinforcing concrete, as required.
In some embodiments the blocks can be selected to mate horizontal tongues of blocks in a second course with corresponding horizontal grooves of blocks in a first course or to allow filling the continuous horizontal groove formed by the horizontal grooves of adjacent blocks in the first course with reinforcing concrete, and subsequently stacking a second course of blocks with flat bottom surfaces, as required.
Yet another embodiment of the invention provides a method of constructing a wall of a plurality of courses of building blocks, the blocks selected from a set of blocks wherein: a first block has a horizontal groove on a top surface, a flat bottom surface, a first end face having a vertical groove and a second end face having a vertical groove; a second block has a horizontal groove on a top surface, a flat bottom surface, a first end face having a vertical groove and a second end face having a vertical tongue; a third block has a horizontal groove on a top surface, a horizontal tongue on a bottom surface, a first end face having a vertical groove and a second end face having a vertical groove; a fourth block has a horizontal groove on a top surface, a horizontal tongue on a bottom surface, a first end face having a vertical groove and a second end face having a vertical tongue, the method comprising steps of: laying a first course of blocks having a flat bottom surface, end-to-end such that where a reinforcing column is not required, adjacent blocks are selected to mate a vertical groove of one block with a corresponding vertical tongue of an adjacent block; or where a reinforcing column is required, adjacent blocks are selected to present facing vertical grooves to form a vertical cavity between the adjacent blocks; filling any vertical cavities in the first course with reinforcing concrete; where horizontal reinforcement is not required, laying a subsequent course of blocks having horizontal tongues to mate with the horizontal grooves of the preceding course below; or where horizontal reinforcement is required, filling the continuous horizontal groove formed by the horizontal grooves of adjacent blocks of the preceding course below with reinforcing concrete and laying a subsequent course of blocks with flat bottom surfaces, end to end; and filling any vertical cavities in the subsequent course with reinforcing concrete.
Some embodiments further comprise a step of gluing adjacent blocks together with a mortar slurry.
Other embodiments further comprise a step of gluing adjacent blocks together with grout.
In some embodiments the vertical spaces of each course align with the vertical spaces of the preceding course below.
Some embodiments further comprise a step of placing reinforcing rods in reinforcing concrete in the aligned vertical cavities.
Some embodiments further comprising a step of placing reinforcing rods in the reinforcing concrete in the continuous horizontal groove.
Other embodiments of the present invention further comprise a step of applying a finish coat directly to the wall, the finish coat selected from the group of mortar, stucco and plaster.
Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings, in which:
The building material is made of straw chopped in lengths of between 5 cm and 10 cm substantially (These are ideal lengths but it can be shorter or longer.) mixed with Portland cement, mortar cement or lime and a polymer emulsion diluted in water which acts as a bonding agent. These different ingredients are well mixed together and then pressed into blocks of different sizes and shapes. The density of the blocks depends on the proportions by which the different ingredients are combined together as well as on the pressure exerted to compress the blocks. The density of the blocks also determines the structural value and the insulation value. Increased density provides more structural value while decreased density provides more insulation value.
The blocks are fabricated in four different shapes that can be used in a building system and method to be either stacked and interlocked or assembled to allow for concrete structural reinforcement.
In an embodiment of the present invention, there are four different shapes of blocks. As shown in
The flexibility to the present invention is illustrated in FIGS. 14 to 19 which show how, by selecting between blocks 2 and blocks 1 and between blocks 4 and blocks 3, render it possible to create at any interval, either vertically or horizontally, a concrete reinforcing structure in a wall.
The embodiments of the invention described above are intended to be exemplary only. The scope of the invention is therefore intended to be limited solely by the scope of the appended claims.
