MXPA00008812A - Fiber reinforced building materials - Google Patents

Abstract

In accordance with the present invention, there are provided novel fiber reinforced building material formulations, comprised of an inorganic binding agent and synthetic fibers. The fibrous material employed in invention formulations is capable of undergoing progressive fibrillation upon agitation. As a result, tougher building materials, due to higher fiber addition rates than previously possible, are produced. Formulations containing Portland cement-based compositions and fibrillating synthetic fibers are also contemplated. In addition, there are provided methods of producing fiber reinforced building materials, including Portland cement-based compositions, and articles produced therefrom.

Description

CONSTRUCTION MATERIALS REINFORCED WITH FIBER FIELD OF THE INVENTION The present invention relates to fiber reinforced construction materials. In a particular aspect the invention relates to methods for the production of synthetic fiber reinforced building materials which, under agitation, progressively fibrillate to produce building materials with improved performance properties. In another aspect of the present invention, articles prepared from the above-described fiber reinforcing materials are provided.

BACKGROUND OF THE INVENTION The concret has the highest production of all man-made materials. Compared with other construction materials, it has many advantages that include low cost, general availability of materials, adaptability and use under different environmental conditions.

Therefore, concrete will probably continue to be the dominant construction material in the foreseeable future.

Unfortunately, flat concrete is also a fragile material with very low tensile strength and deformability, generally requiring reinforcement before it can be used extensively as a building material. The idea of using another material to reinforce a material with low tensile strength is an old concept. For example, straw and horsehair has been used for thousands of years to improve the properties of clay bricks. Bentur, A., Mindess, S., "Fiber Reinforced Cementitious Conposites," (Elsevier Applied Science, 1990). In more recent years, fibers have been incorporated into a wide variety of building materials (including ceramics, plastics, cement, and gypsum products) to improve the performance properties of the resulting composite. American Concrete Institute ACI 544.1R-96, "Fiber Reinforced Concrete," 1996. The introduction of fibers into concrete results in changes in post-elastic property that varies from subtle to substantial, depending on a number of factors including resistance of the matrix, fiber type, fiber module, fiber aspect ratio, fiber resistance, fiber surface bonding characteristics, fiber content, fiber orientation, aggregate size effects , and similar. The improved properties include tensile strength, compressive strength, elastic modulus, cracking resistance, cracking control, durability, fatigue life, impact and abrasion resistance, shrinkage, expansion, thermal characteristics and fire resistance. Although it is known that fiber reinforcement is more effective than conventional reinforcement in the control of local cracking unlike reinforcing bars, it should not provide in most cases any increase in the load bearing capacity of the concrete Conventional reinforcing bars are strategically located in the structure to transport the tensile strengths while the fibers are randomly distributed in the concrete mix. The fibers are therefore not used in designs as a substitute for reinforcement. conventional Although not currently referred to by ACI Committee 318, fibers are sometimes used in structural applications with conventional reinforcement American Concrete Institute, ACI 318 Building Code Requirements for Reinforced Concrete, 1995 The practice of adding steel fibers to concrete to overcome its disadvantages was introduced at the beginning of this century Between 1920 and 1935 several patents pertaining to steel fiber reinforced concrete (SFRC) were granted See for example Kleinlagel, A, German Patent No. 388 959, Scailles, JC, French Patent No. 514 186, Martin, GC, US Patent No. 1,633,219, and Etherpdge, H , North American Patent No. 1, 913,707 The use of glass fibers in concrete was first tried in the USSR in the late 1950s Biryukovich, KL, and Yu, DL, "Glass Flber Reinforced Cement" (translated by GL Cairns, CERA Translation, No 12, Civil Eng Res Assoc, London, 1965) Initial attempts at the use of synthetic fibers (nylon, polypropylene) were made in the 1960s Monfore, GE, "A review of Fiber Reinforced Portland Cement Paste, Mortar and Concrete," J. Res. Dev. Labs, Vol. 10, No. 3, Sept. 1968, pp. 36-42; Goldfein, S., "Plástic Fibrous Reinforcement for Portland Cement," Technical Report No. 1757-TR, U.S. Army Research Development Laboratories, Fort Belvoir, Oct. 1963, pp. 1-16 When steel fibers were used for the first time, only straight steel fibers were used. The use of steel fibers resulted in improved characteristics for ductility and increases in fracture toughness and flexural strength were also reported. For straight steel fibers, two primary factors that controlled the properties of the composite were the fiber volume fraction and the length / diameter or aspect ratio of the fibers. The amount of fibers varied from 90 to 120 kg / m3 (1.1 to 1.5% by volume) of concrete. The aspect ratios were on a scale of 60 to 100. The main problems encountered in the early stages were difficult in mixing and handling. At higher volume fractions it was found that the fibers agglomerate during the mixing process. This process, called agglomeration, occurs frequently for larger fibers. This tends to affect the quality of the concrete, on the site, especially for volume fractions with higher fiber content. In addition, there is a reduction in the workability of the concrete as a result of the addition of the fibers. The arrival of deformed steel fibers in the late 1970s resulted in the increased use of fiber-reinforced concrete in the field. Ramakrishnan stated that fibers with hook ends can be used with fractions of volume much smaller than straight steel fibers, producing the same results in terms of ductility and toughness of the product. Ramakrishnan, V., Brandshaug, T., Coyle, WV, and Shrader, EK, "A Comparative Evaluation of Concrete Reinforced with Straight Steel Fibers and Deformed End Fibers Glued Together in Bundles," ACI Journal, Vol. 77, No. 3 , May-June 1980, pp. 135-143. These fibers were glued to the edges with water soluble glue so that, when added to the concrete, the fibers have a much lower (apparent) aspect ratio. During mixing, the fibers were separated and dispersed as individual fibers. Bonding and subsequent dispersion, in combination with a lower volume fraction of fibers, resulted in the virtual elimination of the agglomeration. Later, a number of other fine fibers such as folded or removed with paddle and elongated ends were also developed. The ACI Committee Report .544 on Fiber Reinforced Concrete, published in 1996, reports that the first significant use of synthetic fibers in concrete was carried out in 1965, by the US Army Corps of Engineers Research and Development Section. American Concrete Institute ACI 544.1R-96, "Fiber Reinforced Concrete," 1996. Synthetic monofilament fibers were used for the construction of concrete structures resistant to explosive wave. The fibers used were 13 to 25 mm long and had an aspect ratio of between 50 to 100, that is, the geometry was not very different from that of the steel fibers that were used in the concrete at that time. With these fibers it was found that addition rates of up to 0.5% by volume of the concrete result in significant increases in ductility and impact resistance. However, there was very little commercial exploitation of fiber reinforcement technology and it was not until the 1980s that the development and large-scale use of synthetic fibers in concrete began to take place. That work was predominantly done with many smaller caliber fibers (ie fibers of smaller diameter with high aspect ratios) at lower fiber addition rates. Morgan, D.R., and Rích, L., "High Volume Synthetic Fiber Reinforced Shotcrete," The First International Conference on Synthetíc Fiber Reinforced Concrete, Orlando Florida, USA, January 16, 1998. Most of the work was done with fibrillated polypropylene fibers interspersed at 0.1 to 0.2% in volume addition regimes. In those regimes of minor fiber volume addition, the primary benefits of the fibers are for the control of plastic shrinkage cracking and the provision of pre-seam strength up to extruded and certain recirculated precast concrete products. The improvement in the ductility of the impact strength and the crack resistance with restricted drying is limited to such low fiber volume addition rates. It should be noted that even in those low fiber addition rates, the fiber cut (number of fibers in one unit of matrix volume) and the specific surface area (fiber surface area per unit volume of the matrix) is very high. As a result, it is currently very difficult to introduce more than 0.4% by volume of conventional fibrillated polypropylene fibers into the concrete without making significant changes to the concrete mix design. As a result, most of the synthetic fibers used today are incorporated into concrete at very low fiber addition rates to simplify the control of plastic shrinkage. With the emergence of new application areas, the interest of the research has moved to higher fiber content where the resistance index and other factors are design considerations. The resistance index is an indication of the load carrying capacities of the fibers within the concrete matrix after the first cracking. As previously mentioned, the. Cast concrete in place will accommodate up to 0.4% by volume of synthetic fibers with minimum mixing ratio adjustments. Concrete with admixture with excess water with fibers added at a rate of up to 0.75% by volume will provide greater increases in the values of toughness index. Morgan, DR, McAskill, N., Richardson, BW, and Zellers, RC, "A Comparative Evaluation of Plain, Poly Propylene Fibers, Steel Fibers, and Wire Mesh Reinforced Shotcrete," Transportation Research Board, Washington DC, Jan. 1989. The length of the fiber and the configuration of the fiber are important factors in this fiber content. In quality concrete applications, the use of fibrillated polypropylene fiber interspersed with contents up to 0.3% by volume has drastically increased fatigue resistance. American Concrete Institute ACI 544.1R-96, "Fiber Reinforced Concrete," 1996. A few years ago, a new monofilament polyolefin fiber with a unique assortment system was developed which has now been used in addition regimes. fiber from 1.0 to 2.0% of volume range (ie values up to 10 times higher than the conventional use of fibrillated polypropylene fibers). The fiber has been used in a range of different flat pieces of concrete and other concrete applications cast in place, for example, deep concrete pavement, bridge deck covering structures, particle finish finishing, etc. Ramakrishnan, V., and MacDonald, C.N., "Durability Evaluation and Performance Histories of Projects Using Polyolefin Fiber Reinforced Concrete," ACI British Columbia Chapter, Hígh Performance Concrete Seminar, Vancouver, BC, April 1997, p.15. The fibers used a length range of 25 to 50 mm and have aspect ratios on the scale of 66 to 80. At these much higher fiber addition rates, ductility, impact strength and toughness in concrete composites they increased substantially and are much more comparable to values achieved with concrete reinforced with steel fiber, with 0.5 to 0.7% (40 to 55 kg / m3) of fiber addition by volume. In addition to demonstrating excellent reinforcement characteristics, polyolefin fiber has the advantage over its steel counterpart that it never rusts. Continuing with the same philosophy (use of polymer fiber in latos- addition regimes), the Synthetics Industries have launched a new polymer for concrete applications. The new fiber called high performance polymer S-152 (HPP), is manufactured as a thick filament with a shaped and designed profile. The product literature of Synthetics Industries in 1998. The wave-like shape of fibers is designed to anchor fibers in concrete. Additionally, the thickness of the fiber allows it to be combined at a much higher rate per unit volume than conventional fibers, thus giving an improved structural performance of concrete application. However, polyolefin fiber is of limited utility because it is a monofilament fiber that will remain in its original form after mixing. It has a relatively short surface area and therefore has correspondingly scarce joining characteristics. Therefore, a relatively large percentage must be introduced by volume (1.5% and above) in order to achieve beneficial results. The addition of concrete fibers will generally result in the loss of settlement and the handling characteristics of the mixture. This loss is amplified according to the aspect ratio (length / diameter) of the fiber or the rate of addition of the fiber is increased. For fiber reinforced concrete mixed in a conventional manner, fibers with a high aspect ratio are more effective in improving post-peak performance due to their high strength for extraction from the matrix. A harmful effect of the use of fibers with a high aspect ratio is the potential for agglomeration of the fibers during mixing. Most of the synthetic fibers used today are fibrilled fibers that have very large surface areas and aspect ratios. The very large surface areas of these fibers make it difficult to produce a mixture of workable concrete at higher fiber addition rates of more than 0.5% by volume, without causing severe problems of handleability and fiber agglomeration. For this reason, synthetic fibers are mainly used at 0.1% by volume of fiber addition regimes, and are mostly added for the control of contraction cracking in concrete. Therefore, there is a need in the art for fiber reinforced concrete formulations that overcome the aforementioned disadvantages, while still maintaining superior shrinkage and handling characteristics. More particularly, it would be desirable to be able to use fibers of a type which is less sensitive to agglomeration and which can therefore be added in larger volume fractions. Larger volume fractions will result in improved reinforcement characteristics, previously unattainable with fiber reinforced construction materials such as concrete.

BRIEF DESCRIPTION OF THE INVENTION The present invention solves the aforementioned needs in the art by providing fiber-reinforced construction materials such as concrete, which has improved performance properties such as reduced plastic shrinkage, reduced shrinkage shrinkage, improved fire, improved fatigue longevity, improved resistance to thermal expansion and shrinkage, improved toughness index, improved handling and handling, and the like. The reinforced building materials of the invention are prepared using fiber material having defined initial properties and the specific ability to fibrillate resulting in a surface area substantially increased upon mixing. The initial low surface area of the fiber material contemplated for use in accordance with the invention allows the addition of a relatively high fiber content without making changes in the concrete mixing design or using any releasable bonding agent over time to Avoid the agglomeration of fibers. The ability of the fibrous material used in the present to withstand progressive fiberization allows a uniform fiber distribution to be achieved throughout the entire concrete mix in the early stages of mixing while the fibers are still relatively intact. Subsequently, when the fibers begin to fibrillate, they do not have at this stage to agglomerate since they have been well dispersed in the concrete mixture.

BRIEF DESCRIPTION OF THE FIGURE. Figure 1 graphically graphs the flexural tenacity curve of a "concrete" formulation containing 1.5 vol.% Monofilament fibers having performance / physical properties as described for use in the practice of the present invention . Subsequently, when the fibers begin to fibrillate, they do not tend, at this stage, to agglomerate since they have been dispersed in the concrete mixture. More specifically, the present invention provides a product formulation of construction comprising a mixture containing an inorganic binder and in the range from about 0.1 to about 3.0% by volume of a fibrous material, wherein the fibrous material is composed of monofilaments of synthetic resin and wherein the fibrous material is characterized as having: an initial surface area of each monofilament of the fibrous material of not more than about 200 mm 2; wherein the fibrous material undergoes a progressive fibrillation under agitation of the formula, resulting in an increase in the surface area of the fibrous material. The present invention also provides a formulation based on Portland cement comprising in a range from about 0.1 to about 0.3 volume% of a fibrous material comprising Portland cement, wherein the fibrous material is composed of synthetic resin monofilaments and wherein the fibrous material is characterized as having: an initial surface area of each monofilament of the fibrous material of not more than about 200 mm2; wherein the fibrous material undergoes progressive fibrillation under the agitation of said formulation, resulting in an increase in the surface area of the fibrous material. The present invention also provides a method for the production of a formulation based on Portland cement, the method comprising adding on the scale from about 0.1 to about 0.3% by volume of a fibrous material to a composition based on Portland cement, in wherein the fibrous material is composed of synthetic resin monofilaments and wherein the fibrous material is characterized as having: an initial surface area of each monofilament of the fibrous material of not more than about 200 mm2; wherein the fibrous material undergoes a progressive fibrillation low agitation of the formulation, resulting in an increase in the surface area of the fibrous material. The present invention also provides a method for producing a product formulation of construction, the method comprising: (a) adding on the scale from about 0.1 to about 0.3% by volume of a fibrous material to an inorganic binder; wherein the fibrous material is composed of synthetic resin monofilaments and wherein the fibrous material is characterized as having: an initial surface area of each monofilament of the fibrous material of not more than about 200 mm 2; (b) shaking the resulting combination to cause progressive fibrillation resulting in an increase in the surface area of the fibrous material. The present invention also provides an article comprising a formulation based on reinforced Portland cement, the formulation containing on the scale from about 0.1 to about 3.0 by volume of a fibrous material, wherein the fibrous material is composed of synthetic resin monofilaments. and wherein the fibrous material is characterized as having: an initial surface area of each monofilament of the fibrous material of no more than about 200 mm2, wherein the fibrous material has undergone the progressive fi liation under agitation of said formulation, resulting in an increase in the surface area of the fibrous material The present invention also provides a fibrous material for use in a construction product formulation, comprising synthetic resin monofilaments each having an initial surface area of no more than about 200 mm2. , where the fibrous material exp Increase in progressive fires under agitation resulting in an increase in surface area BRIEF DESCRIPTION OF THE FIGURE Figure 1 graphically illustrates the flexural tenacity curve of a "concrete" formulation containing 1 5% by volume of monofilament fibers having performance / physical properties as described for use in the practice of the present invention DETAILED DESCRIPTION OF THE INVENTION According to the present invention, formulations of construction product are provided which comprise a mixture containing inorganic binder and in the range from about 0 1 to about 30 percent by volume of a fibrous material, in where the fibrous material is characterized by having (a) a low initial aspect ratio, (b) an initial surface area of no more than approximately 200m2, where the fibrous material is capable of and undergoes progressive fibrillation under agitation of the formulation, resulting in an average increase in the surface area of at least about 20 percent, preferably of at least about 50 percent. Also provided herein are production methods of the above-described product formulation for construction as well as the articles comprising the formulation As used herein, "product formulation for construction" refers to a variety of construction materials and matrices including, Portland cement based formulations and articles produced therefrom, such as concrete, concrete, bricks, mortar, mortar, upper parthumos, synthetic compounds, carbon-based compounds and the like In a modal Preferred embodiment of the invention, the Portland cement based formulation is concrete comprising Portland cement, rocks (such as gravel or crushed rock) and sand. Those skilled in the art can easily identify the inorganic binder materials suitable for use in the FIELD OF THE PRESENT INVENTION As used herein, the term "fibrous material" refers to a synthetic monofilament that tends to separate by progressive fiber cleavage, typically from the ends of the fibers inwardly (i.e., "fibrillated"). ), under appropriate conditions, in a plurality of filaments of various lengths from full length to a small microscopic one, each of areas of cross section much smaller and higher aspect ratio than the original monofilament. Of course, it is recognized by those skilled in the art that fibrous matter can not be completely divided or separated, but can remain as a unit composed of a plurality of fibrils (i.e., can fibrillate partially). In one aspect of the present invention, a population of large, short, bound and separated fibrils can be expected under the appropriate conditions. Suitable conditions for generating the fully and partially fibrillated fibers include agitation, mixing, vibration, spraying and the like. The resulting variety in fiber size and the aspect ratios of the fibrillated fibers will contribute to a scale of improved characteristics such as manageability, toughness and resistance to shrinkage. The fibrous material contemplated for use herein typically possesses such desirable performance properties as elasticity, tensile strength, toughness, resistance to changes in pH and resistance to moisture, sufficient to make such materials useful for waterborne formulations. Reinforced construction product under standard loads and conditions. In a specific embodiment, the fibrous material contemplated for use herein is comprised of flat, folded and / or etched fiber articles. In another aspect of the present invention the initial cross-sectional dimensions of the original synthetic monofilament are approximately 1.1mm x 0.37mm. According to another specific aspect of the invention, the fibrillated or partially fibrillated fibrous material comprises a fine network structure of fibers of a synthetic polymer combination. As used in the present "network structure", it adheres to the normal use of the term, that is, fibrillated and partially fibrillated fibers form a relatively disordered mesh structure or similar to tangled network. The modified "fine", as used in the phrase "fine network structure", denotes the inherently small nature of the network due to the size, of the fibers described herein for use in the compositions and methods of the invention. Examples of suitable synthetic polymer blends contemplated for use herein include blends of polypropylene polymer and polyethylene. Preferably the polyethylene / polypropylene mixture employed herein will have a mass of about 7.5 g per denier, a specific gravity of about 0.94 and an elongation to stretch at break in the range of about 16% to about 18%. In this preferred embodiment, the polymer combination is in the range of about 70 to about 90% polypropylene resin having a melt flow rate in the range of about 1 2 to about 4 g / 10 min and a specific gravity in the scale from about 0 88 to about 0 90 g / cm3 The other component of the currently preferred polymer blend is in the range from about 10 to about 30% of high density polyethylene resin with a melt flow rate in the scale from about 0 6 to about 1 1 g / 10 min and a specific gravity in the scale from about 0 94 to about 0 96 g / cm 3 In a preferred aspect of the invention, the fibrous network consists of the combination of polyethylene polymer / polypropylene previously described exclusively and not held together by any type of adhesive agent. The fibers illustrative of The type is made under the name "Polysteel ™" and is available from East Coast Rope Ltd, Sydney, Nova Scotia, Canada. Fibers contemplated for use in accordance with the compositions and methods of the invention can be produced by any method. known in the art In one aspect of the present invention, the fibers contemplated for use in the practice of the invention are manufactured by individually extruding a filament that is subsequently extinguished and then drawn in a stretching oven. The filament is reheated in a recosido furnace to relax the filament and fix the "memory" of the filament The filament can be engraved to create flexibility and improve the clamping capacity of the filament Finally, the filament is cut to the specified length (depending on the application) using, for example, a rotating cutting wheel Of course, as will be easily recognized by those with experience in the art , other methods suitable for producing fibers that meet the fiber specifications set forth herein may also be employed. As used herein, "aspect ratio" means the length of a fiber divided by the diameter of a cylindrical fiber having an area of similar cross section According to the present invention, the fibrous material employed has a low initial aspect ratio. Suitable aspect ratios can easily be determined by those skilled in the art. Typically the initial aspect ratio will be on the scale of about 30 to about 80 As will be readily understood by those skilled in the art, any value on the scale described above may be employed in the practice of the present invention, depending on the particular formulation of the compositions of the invention, the intended use, the or the desired properties of the compositions of the invention and the like For example, in one aspect of the invention, when preparing formulations useful for pumped concrete (e.g. "concrete"), the initial aspect ratio should be at the lower end of the scale, typically it should be around 50. In another aspect of the invention, when preparing useful formulation for concrete casting or casting at the site (such as plates) the initial aspect ratio should be at the upper end of the scale, typically around 70. As will be readily recognized by those with Experience in the art, a wide range of fiber lengths is suitable for use in the practice of the present invention. As will be understood by those skilled in the art, the length of the fibers to be employed in the practice of the present invention will vary depending on the compositions of the invention, the intended use, the desired properties of the compositions of the invention and Similar. For example, in one aspect of the invention, when preparing formulations useful for pumped concrete, the initial fiber length for the fibrous material contemplated for use herein will be relatively short, typically around 38 mm. In another aspect of the invention, when preparing formulations useful for concrete casting or casting in place, the length of the fiber will be somewhat larger, commonly around 50 mm. As used herein, the "low initial surface area" contemplated for the fibrous material used herein is not greater than about 200 mm2. It is currently preferred that the initial surface area be less than about 150 mm2 In a specific embodiment for use in the preparation of compositions based on Portland cement that are pumped (eg, "concrete" and the like), an initial surface area of about 110 mm2 is preferred In a specific embodiment for use in the preparation of Portland cement based compositions that are emptied or poured in place, the preferred initial surface area is approximately 150 mm2 As used herein. "agitation" refers to any means of combining / mixing the contents of the formulations of the invention. All means are contemplated for use in the practice of the present invention. Agitation may be achieved by mechanical means, such as, for example, mixing. , turning, shaking, shaking, pouring, kneading, vibrating, pumping and the like The additional means of agitation n contemplated for use in the present invention include ultrasonic vibration and thermally induced mixing or turbulence. In a currently preferred embodiment, agitation will occur through the mechanical action of a cement mixer. The use of the term "fibrillation" in the claims and specification of the present refer to the progressive separation or division of the fibrous material of low initial surface area into individual members of the fibrous network of the component. In a given population of the fibrous material that has experienced fibrillation, part of the fibrous material area of The initial low surface area may remain substantially intact and not separated, while other initial fibers may be completely and substantially separated. According to the present invention, after fibrillation, there will be a separate range of fibers resulting in an average increase in the surface area of the population of the fibrous material in the scale of at least about 20 percent, preferably of at least about 50 percent In a particularly preferred embodiment, the fibrous material will experience an average increase in the surface area of at least 100 percent. In a particularly preferred embodiment, the population of fibers will represent an average increase in the surface area of the fibrous material of at least 200 percent. In a preferred embodiment of the present invention, the progressive fi bp of the fibers allows an almost uniform distribution of the fibers through the concrete mix in the early stages of mixing, while the fibers are still relatively intact (ie before the fiblage itself). As will be readily understood by those skilled in the art, even the lightest increase in the surface area of the fiber (eg 5% and more) caused by a minimum level of insulation will lead to improvements in performance properties. general (for example, flexural tenacity, plastic shrinkage, shrinkage to drying, fire resistance, fatigue life, resistance to thermal expansion and shrinkage, impact resistance, handling, pumping and handling and the like) of the materials of construction reinforced with fiber over that achieved with the original monofilament fiber (ie not fibrillated). The most substantial increases (for example in the scale of at least about 50%) in the surface area of the fiber will lead to significant improvements in performance properties. The fibrillation of the fibers contemplated for use in accordance with the present invention will lead to increases in the average in the surface area of the fibrous material up to about 20,000% or more. Despite these average values, those skilled in the art will readily recognize that even at greater percentage increases in the surface area, some fibers will remain intact and will not show visible increases in the surface area after mixing and placement. In accordance with one aspect of the present invention, construction product formulations comprising the fiber material described herein are provided in the scale from about 0.1 to about 3.0 volume percent. Such construction product formulations show improved characteristics when compared to other fiber reinforced construction formulations such as reduced plastic shrinkage, reduced drying shrinkage, improved fire resistance, improved fatigue longevity, improved thermal expansion and heat resistance. shrinkage, improved impact strength, improved flexural toughness, improved workability, pumping and handling and the like According to another aspect of the present invention, product formulations for construction are provided which comprise the scale from about 0 1 to about 0 3 percent by volume of the fiber material described herein At those low ranges of fiber addition, such formulations demonstrate improved characteristics such as plastic shrinkage, shrinkage to drying, improved fire resistance, improved fatigue life, improved strength the thermal expansion and shrinkage, improved workability, pumping and handling, as well as some improvement in impact strength and flexural toughness. In yet another aspect of the present invention, construction product formulations comprising the scale are provided. from about 0 3 to about 30 percent by volume of the fiber material described in present A at those relatively high fiber addition rates, such formulations also demonstrate improved characteristics such as plastic shrinkage, shrinkage to drying, improved fire resistance, improved fatigue longevity, improved resistance to thermal expansion and shrinkage, improved handling, pumping and handling, as well as substantial improvements to impact strength and flexural toughness. According to another embodiment of the present invention, methods are provided for produce product formulations d construction by adding the fibrous material described above to inorganic binding materials wherein the formulation is subjected to sufficient agitation to achieve an average increase in fiber surface area of at least about 20 percent, preferably of at least about 50 percent. Those methods produce construction materials that they have when compared to other synthetic fiber reinforcement systems, improved characteristics such as reduced plastic shrinkage, shrinkage to reduced drying, improved fire resistance, improved fatigue longevity, improved resistance to thermal expansion and shrinkage, improved impact strength, improved flexural toughness, improved handling, pumping and handling and the like In one aspect of the methods of the invention, on the scale of about 0 1 to about 0 3 volume percent of the fibrous material is added to a composition based on Portland cement which is then subjected to stirring as before, thereby providing formulations of construction product with improved characteristics such as plastic shrinkage, shrinkage to drying, resistance to fu Improved ego, improved fatigue longevity, improved resistance to thermal expansion and shrinkage, improved handling, improved pumping and handling, as well as some improvement in impact resistance and flexural tenacity. In another aspect of the methods of the invention in the scale from about 0.3 to about 3.0 volume percent of a fibrous material is added to a composition based on Portland cement which is then subjected to stirring as above, providing this way, product formulations for construction with plastic shrinkage, shrinkage to drying, improved fire resistance, improved fatigue longevity, resistance to thermal expansion and shrinkage, improved handling, pumping and handling, as well as substantial improvements in impact resistance and flexural tenacity. According to another embodiment of the present invention, articles are provided that comprise the formulations of the construction product described above. In a preferred aspect of the invention they provide articles comprising the Portland cement-based formulations described above. The invention will now be described in greater detail by reference to the following non-limiting examples.

EXAMPLES In a recent experiment it was shown that the 3000 denier Polysteel ™ fiber (available from East Coast Rope, Ltd., North Sydney, Nova Scotia), which comprises polyethylene / polypropylene polymer blend with a mass of about 7.5 grams per denier, a specific gravity of about 0.94 and an elongation to stretch at the break in the range of about 16% to about 18%, when added to a volume addition rate of 1% improved polyolefin fiber to 1.67% by volume ( fiber of similar initial surface area, and identical tensile strength and modulus of elasticity) both in flexural tenacity and in plastic shrinkage performance. Similar tests were conducted on a series of steel fibers at 0.5 and 0.75% fiber addition rates; the results show that fibrillation fiber, when added to a 1% volume addition rate, improved easily to steel fibers in plastic shrinkage control and shrinkage drying. The concrete tests were conducted on fiber, having performance and physical properties described herein, which reveal that the fiber is easily pumped and loaded in fractions of fiber volume of up to 1.5%. A slight change in the concrete mix design allowed the fiber to be pumped and loaded to a high percentage addition rate of 2% by volume. It should be noted that it is almost impossible to pump and load the fibrillated synthetic fibers available in the market at addition rates exceeding 0.5% by volume. Again, the initial low fiber surface area of the monofilament fiber allowed the addition of a very high amount of fibers in the concrete. In the case of concrete, the action of fibrillation was produced by the action of the concrete mixer and by the impact of the fibers on the projected surface. The results, as illustrated in Figure 1, indicate that the fibrillation fiber has achieved a level of V toughness at 1.5% addition, a performance never achieved by any synthetic fiber before. The fiber addition rates of 1% in fibrillation fiber concrete achieved the level of yield to IV toughness, which again is substantially higher than other synthetic fibers. While the invention has been described in detail with reference to certain preferred embodiments thereof it will be understood that the modifications and variations are within the scope and spirit for which it was described and claimed.

Claims (1)

1. CLAIMS 1 A product formulation for construction comprising a mixture containing inorganic binding agent and in the range of about 0 1 to about 30 percent by volume of a fibrous material in which the fibrous material is composed of synthetic resin monofilaments and wherein the fibrous material is characterized as having an initial surface area of each monofilament of the fibrous material of no more than about 200m2, wherein the fibrous material undergoes progressive fibrillation under the agitation of the formula, resulting in an increase in the area of surface of the fibrous material 2 A formulation based on Portland cement comprising Portland cement and in the range of about 0 1 to about 3 0 percent by volume of a fibrous material, wherein the fibrous material is composed of synthetic ream monofilaments and where the fibrous material is characterized by t ener, an initial surface area of each monofilament of the fibrous material of no more than about 200 mm2, wherein the fibrous material undergoes progressive fibrillation under agitation of said formulation, resulting in an increase in the surface area of the fibrous material. A formulation according to claim 1 or 2, characterized in that the increase in the surface area of the fibrous material is on average, of at least about 20 percent. 4 A formulation according to the claim 1 or 2, characterized in that each monofilament of the fibrous material has an aspect ratio in the range of about 30 to about 80 before agitation. A formulation according to claim 1 or 2, characterized in that the fibrous material comprises one of the flat fibers, bent fibers and engraved fibers 6 A formulation according to claim 1 or 2, characterized in that the fibrous material is comprised of a fine network structure of filaments 7 A formulation according to any of claims 1 to 6, characterized because the monofilaments of synthetic resin comprise a combination of polypropylene and polyethylene 8 A formulation according to claim 7, characterized in that the fibrous material has a mass of approximately 7 5 grams per denier, a specific gravity of approximately 0 94 and an elongation by voltage of approximately 16% up to About 18% 9 A formulation according to claim 1 or 2, comprising on the scale from about 0 1 to about 0.3 volume percent of the fibrous material. 10. A formulation according to claim 1 or 2, which comprises on the scale from about 0.3 to about 3.0 volume percent of the fibrous material. 11. A method for the production of a formulation based on Portland cement, the method comprising adding on the scale from about 0.1 to about 3.0 volume percent of a fibrous material to a composition based on Portland cement, wherein the fibrous material is composed of synthetic resin monofilaments and wherein the fibrous material is characterized as having: an initial surface area of each monofilament of each monofilament of the fibrous material of not more than about 200 mm 2; where the fibrous material undergoes progressive fibrillation under agitation of the formulation, resulting in an increase in the surface area of the fibrous material. 12. A method for producing a product formulation for construction, the method comprising: (a) adding on a scale from about 0.1 to about 3.0 volume percent of a fibrous material to an inorganic binding agent, wherein the material fibrous is composed of synthetic resin monofilaments and wherein the fibrous material is characterized as having: an initial surface area of each monofilament of fibrous material of not more than about 200 mm2; (b) shaking the resulting combination to cause the progressive fibrillation to result in an increase in the surface area of the fibrous material. 13. A method according to claim 11 or 12, characterized in that the increase in the surface area of the fibrous material is on average at least about 20 percent. A method according to claim 11 or 12, which comprises adding an amount of effective fibrous material to improve plastic shrinkage and / or contraction characteristics upon drying of the product formulation for construction. 15. A method according to claim 11 or 12, which comprises adding a quantity of effective fibrous material to improve the flexural toughness characteristics of the formulation of the construction product. 16. A method according to claim 11 or 12, which comprises adding a quantity of effective fibrous material to improve cracking resistance and cracking control of the construction product formulation. 17. A method according to claim 11 or 12, comprising adding a quantity of fibrous material: ective to improve the fatigue life of the construction p oducts formulation. 18. A method according to claim 11 or 12, comprising adding a quantity of fibrous material : ective to improve resistance to thermal expansion or thermal construction of the product formulation for construction. 19. A method according to claim 11 or 12, comprising adding a quantity of effective fibrous material to improve the fire resistance of the formulation of the construction p-oduct. 20. A method according to claim 11 or 1J2, comprising adding a quantity of reagent fibrous material to improve the impact resistance of the construction p oducts formulation. 21. A method according to claim 11 or 12, comprising adding a quantity of fibrous material : ective to improve the characteristics of relative handling of the formulation of the construction product. 22. A method according to claim 11 or 12, comprising adding a quantity of effective fibrous material to improve the relative pumping characteristics of the formulation of the construction product. 23. A method according to claim 11 or 12, characterized in that each monofilament of the fibrous material has an aspect ratio on the scale of about 30 to about 80 prior to agitation. 24. A method according to claim 11 or 12, characterized in that the fibrous material comprises at least one of the flat fibers, folded fibers and engraved fibers. 25. An article comprising a formulation based on reinforced Portland cement, the formulation containing the scale from about 0.1 to about 3.0 volume percent of a fibrous material, wherein the fibrous material is composed of synthetic resin monofilaments and in where the fibrous material is characterized as having: an initial surface area of each filament of the fibrous material of not more than about 200 mm2; wherein the fibrous material has undergone progressive fibrillation under agitation of said formulation, resulting in an increase in the surface area of the fibrous material. 26. An article according to claim 25, characterized in that the increase in the surface area of the fibrous material is, on average, at least about 20%. 27. An article according to claim 25, characterized in that each monofilament of the fibrous material has an aspect ratio on the scale of about 30 to about 80 prior to agitation. An article according to claim 25, characterized in that the fibrous material comprises at least one of the flat fibers, folded fibers and etched fibers 29 A fibrous material for use in a construction product formulation comprising monofilaments of synthetic resin, each having an initial surface area of no more than about 200 mm2, wherein the fibrous material undergoes progressive fi ltration under agitation resulting in an increase in the surface area 30 The fibrous material according to claim 29, characterized because the increase in the surface area of the fibrous material is on average, of at least about 20 percent. The fibrous material according to claim 29, characterized in that each monofilament of the fibrous material has an aspect ratio in the range from about 30 to about 80 before stirring 32 The fibrous material according to claim 29, characterized in that the fibrous material comprises at least one of the flat fibers, folded fibers and etched fibers. The fibrous material according to any of claims 25 to 32, characterized in that the resin monofilaments Synthetic comprise a combination of polypropylene and polyethylene