Dry-cast lightweight veneer block, system, and method
11454034 · 2022-09-27
Assignee
Inventors
Cpc classification
E04F13/14
FIXED CONSTRUCTIONS
C04B20/008
CHEMISTRY; METALLURGY
C04B30/00
CHEMISTRY; METALLURGY
C04B20/008
CHEMISTRY; METALLURGY
C04B28/02
CHEMISTRY; METALLURGY
C04B28/02
CHEMISTRY; METALLURGY
C04B2111/00051
CHEMISTRY; METALLURGY
E04F13/0885
FIXED CONSTRUCTIONS
International classification
E04F13/08
FIXED CONSTRUCTIONS
E04F13/14
FIXED CONSTRUCTIONS
C04B28/02
CHEMISTRY; METALLURGY
C04B18/02
CHEMISTRY; METALLURGY
Abstract
Described are dry cast lightweight veneer blocks and a system and method of installing lightweight veneer blocks. The courses can be assembled without mortar between the courses. As an example, sides of the veneer blocks have areas that recede from an imaginary plane between adjacent veneer blocks to give a deep texturing and a shadow effect between veneer blocks. The installation system and method include a substrate, an air barrier applied to the substrate, a plurality of veneer blocks, and an adhesive applied between the plurality of veneer blocks and the air barrier.
Claims
1. A concrete veneer unit comprising a lightweight aggregate constituent material, one or more sand constituent materials and a cementitious constituent material, wherein: (a) the lightweight aggregate constituent material conforms with the requirements of ASTM C1670 for Lightweight Aggregates designated as such in ASTM C1670; (b) the one or more sand constituent materials each conform with the requirements of ASTM C1670 for Normal Weight Aggregates designated as such in ASTM C1670; (c) the average thickness of the concrete veneer unit, as determined according to ASTM C1670, does not exceed 2⅝ inches; (d) no face dimension of the unit, as determined according to ASTM C1670, exceeds 36 inches; (e) the total face area of the unit, as determined according to ASTM C1670, does not exceed 5 square feet; the weight per square foot, as determined according to ASTM C1670, does not exceed 15 pounds per square foot; and (g) the saturated density of the unit, as determined according to ASTM C1670, is at least 99 pounds per cubic foot.
2. The concrete veneer unit of claim 1, wherein the one or more sand constituent materials comprise a fine sand component having a fineness modulus less than 2.
3. The concrete veneer unit of claim 2 wherein, together the lightweight aggregate constituent material and the one or more sand constituent materials define an aggregate constituent, and the proportions of the lightweight constituent material and the fine sand component in the aggregate constituent are 35-45% by weight lightweight aggregate constituent material and 25-35% by weight fine sand component.
4. The concrete veneer unit of claim 2, wherein the one or more sand constituent materials further comprises a coarse sand component having a fineness modulus greater than 2.
5. The concrete veneer unit of claim 4 wherein, together the lightweight aggregate constituent material and the one or more sand constituent materials define an aggregate constituent, and the proportions of the lightweight constituent material and the fine sand component in the aggregate constituent are 35-45% by weight lightweight aggregate constituent material and 25-35% by weight fine sand component.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) In the following detailed description, embodiments of the invention are described referring to the following figures:
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DETAILED DESCRIPTION
(23) The subject matter of embodiments of the present invention is described here with specificity to meet statutory requirements, but this description is not necessarily intended to limit the scope of the claims. The claimed subject matter may be embodied in other ways, may include different elements or steps, and may be used in conjunction with other existing or future technologies. This description should not be interpreted as implying any particular order or arrangement among or between various steps or elements except when the order of individual steps or arrangement of elements is explicitly described.
(24) Dry-Cast Lightweight Veneer Mix Design
(25) The dry-cast lightweight veneer blocks (“DCLV blocks”) described below and in the claims of this patent may be construction materials manufactured of any suitable dry cast materials, including but not limited to cement, sand, and aggregates. In some cases, additional and/or alternative ingredients may be used, which may include but are not limited to other masonry products, structural foams, plastics, plastic composites, reinforced plastics, filled plastics, and polymer materials. In certain embodiments, the mixture used to form the DCLV blocks may comprise course sand, fine sand, and lightweight aggregate.
(26) It will be understood that the term “fine sand” generally refers to sand in which the majority of particles have a particle size less than 600 μm, and more specifically refers to sand in which over 70% of particles have a particle size in a range of 300 μm-600 μm. Examples of fine sand include but are not limited to silica sand.
(27) It will also be understood that the term “coarse sand” generally refers to sand in which the majority of particles have a particle size greater than 300 μm, and more specifically refers to sand in which over 60% of particles have a particle size in a range of 300 μm-2 mm. Examples of coarse sand include but are not limited to FA2 sand.
(28) The lightweight aggregate may include but is not limited to gravelite, expanded shale, pumice, slag aggregate, etc.
(29) A Fineness modulus (“FM”) is an empirical figure defined mathematically as the sum of the cumulative percentages retained on standard sieves divided by 100. Standard size sieves are ⅜ in (9.5 mm), No. 4 (4.75 mm), No. 8 (2.36 mm), No. 16 (1.18 mm), No. 30 (600 μm), No. 50 (300 μm), and No. 100 (150 μm). FM is an index of the fineness of an aggregate, the higher the FM, the coarser the aggregate. In certain embodiments, fine sand may have a FM of less than 2, and course sand may have a FM of greater than 2. However, these are merely ranges for certain embodiments, and other values outside these ranges may be included in both categories.
(30) The ratio of lightweight aggregate to the course and fine sand matrix results in a density of 105 lb/ft.sup.3 or less, whereas traditional dry cast products have a density of approximately 140-141 lb/ft.sup.3. The greater density associated with dry-cast products has traditionally made it very difficult to use dry-casting as a way to produce lightweight veneers, particularly since ASTM standards limit the maximum weight of veneers to 15 lb/ft.sup.2, a value easily attained with wet cast products due to the predominance of lightweight aggregates.
(31) For comparison, a DCLV block of 1⅝ in (nominal) thickness has overall dimensions of 1⅝ in ×12 in ×12 in (or 235.275 in.sup.3 or 0.136 ft.sup.3). A maximum density of the DCLV block at 15 lb/ft.sup.2 is 110.17 lb/ft.sup.3. Table I below show the correlation between other densities for a DCLV block of these dimensions.
(32) TABLE-US-00001 TABLE I Correlation between other Densities for a DCLV Block. 105 lb/ft.sup.3 14.296 lb/ft.sup.2 103 lb/ft.sup.3 14.024 lb/ft.sup.2 101 lb/ft.sup.3 13.752 lb/ft.sup.2 99 lb/ft.sup.3 13.479 lb/ft.sup.2
(33) When lightweight aggregate was initially introduced into the dry cast mixture during early testing, the lightweight aggregate tended to disperse to the surface of the DCLV blocks, giving it an undesirable “popcorn ceiling” appearance. To temper that look, the ratios of various gradations of sand were evaluated to determine how to prevent the migration of the lightweight aggregate to the surface, while also keeping the weight from exceeding the threshold amount. To achieve the desired balance of the conflicting properties, fine sand may be added to the aggregate in a range of 25%-35% by weight, depending on graduations of the other aggregates, to provide a tight texture. The lightweight aggregate may be added in a range of 35%-45% by weight, depending on graduations and weight of the other aggregates, and may be added to ensure that the blend has a maximum weight of 15 lb/ft.sup.2. The protocol for measuring this value is described in ASTM C1670/C1670M. In some embodiments, the amount of lightweight aggregate may be as low as 30% by weight. Coarse sand may be added as a filler in any suitable range that provides the appropriate weight and properties. The mixture of both fine and coarse sand allows the dry-cast product to achieve the necessary weight below the ASTM maximum threshold value of 15 lb/ft.sup.2, while also allowing the mixture to have a smooth surface appearance.
(34) In certain embodiments, color pigmentation is added directly with the other ingredients to form the mixture, rather than adding it to the surface of a mold. As a result, the coloration extends through the entire DCLV block, and chipping or damaging the surface of the DCLV block does not reveal any unpigmented inner portions.
(35) Likewise, the surface of the DCLV block can be cleaned like any standard masonry without concern that such treatment will remove surface pigmentation and expose unpigmented inner portions below.
(36) To prepare the DCLV blocks, the mixture is prepared and introduced into a steel mold. Pressure is then applied to the mixture with a shoe so that the mixture hardens into the DCLV blocks. By forming the mold from steel (or other suitably rigid material), the DCLV blocks can be made with a high level of precision, otherwise not possible with latex molds, urethane molds, or other flexible molds. The use of steel or otherwise rigid molds is not possible with wet cast concrete because there is no way to remove the wet cast product from the mold after it has dried and hardened.
Examples
(37) 32% by weight (1415 lb) silica sand, 27% by weight (1195 lb) FA2 sand, and 41% by weight (1810 lb) lightweight aggregate (gravelite) were combined form a lightweight aggregate blend. The resulting particle size distribution is summarized in Table II below.
(38) TABLE-US-00002 TABLE II Distribution in Particle Size within Each Component. Silica Sand FA2 Sand Gravelite Sieve Grams % % Grams % % Grams % % Size Ret. Ret. Accum Ret. Ret. Accum Ret. Ret. Accum ⅜″ 0.0 0.0% 0.0% 0.0 0.0% 0.0% 0.0 0.0% 0.0% (9.5 mm) #4 0.0 0.0% 0.0% 1.6 0.2% 0.2% 25.2 7.6% 7.6% (4.75 mm) #8 0.0 0.0% 0.0% 63.7 8.2% 8.4% 90.6 27.4% 35.1% (2.36 mm) #16 0.0 0.0% 0.0% 109.2 14.1% 22.5% 88.3 26.7% 61.8% (1.18 mm) #30 8.6 1.0% 1.0% 191.8 24.8% 47.3% 55.6 16.8% 78.7% (600 μm) #50 656.0 76.7% 77.7% 168.8 21.8% 69.1% 30.8 9.3% 88.0% (300 μm) #100 183.8 21.5% 99.2% 219.2 28.3% 97.4% 14.3 4.3% 92.3% (150 μm) Pan 6.5 0.8% 100.0% 20.3 2.6% 100.0% 25.3 7.7% 100.0% Total 854.9 FM= 1.78 774.6 FM= 2.45 330.1 FM= 3.64
(39) A Hillcrest dry cast lightweight veneer product, which is also shown in
(40) TABLE-US-00003 TABLE III Test Results for Eldorado Limestone Wet Cast Lightweight Veneer. Absorp- Compressive Strength Density tion ASTM C170 ASTM C140 MPa PSI Kg/m3 Lb/ft3 % # A 27.8 4032 1262 78.78 19.6 sam- B 27.4 3974 1261 78.72 19.6 ple C 33.7 4888 1261 78.72 18.6 D 32.0 4641 1260 78.66 19.9 E 31.6 4583 1256 78.41 19.6 F 33.7 4888 1265 78.97 19.0 Average 31.0 4501 1261 78.7 19.4 Min 27.4 3974 1256 78.4 18.6 Max 33.7 4888 1265 79.0 19.9 Std Dev 2.6 370 2.7 0.2 0.4 Ecart min 11.7% 0.4% 4.0% Ecart max 8.6% 0.3% 2.7% Max var/avg 12% 0.4% 4.0%
(41) TABLE-US-00004 TABLE IV Test Results for Hillcrest Dry Cast Lightweight Veneer. Absorp- Compressive Strength Density tion ASTM C170 ASTM C140 MPa PSI Kg/m3 Lb/ft3 % # 1 44.9 6512 1697 105.94 6.0 sam- 2 34.4 4989 1656 103.38 6.0 ple 3 35.0 5076 1666 104.00 6.1 4 44.1 6396 1664 103.88 5.8 5 45.4 6584 1700 106.13 6.1 6 45.7 6628 1691 105.57 5.6 7 32.8 4757 1647 102.82 5.7 Average 40.3 5849 1674 104.5 5.9 Min 32.8 4757 1647 102.8 5.6 Max 45.7 6628 1700 106.1 6.1 Std Dev 5.5 794 19.7 1.2 0.2 Ecart min 18.7% 1.6% 5.1% Ecart max 13.3% 1.5% 3.4% Max var/avg 19% 1.6% 5.1%
(42) In these test results, the variation in the Hillcrest Dry Cast Lightweight Veneer and the Eldorado Limestone Wet Cast Lightweight Veneer for compression tests is higher than required by AC51, but minimum results are still very high in comparison with the 1800 psi minimum. In fact, the dry cast veneer process generates products with 4-5 times higher psi than the wet cast process, which is particularly noticeable when compared to the AC51 standard, which sets a minimum limit for psi at only 1800 psi and which was developed based on wet cast veneer products.
(43) The lower absorption rate/integral water repellent and higher psi values also act to minimize freeze/thaw damage to the DCLV block. To confirm, the aggregate mixture was tested for freeze-thaw, according to ASTM C666/C666M and NQ2624-120. Veneer specimens were prepared using the aggregate mixture and tested with the NQ2624-120 standard (except that salt water was replaced with fresh water) and ASTM C666/C666M.
(44) Each specimen's resistance to freezing and thawing was tested. According to the test protocol, the specimens must not break or disintegrate, and weight loss is limited to 3% of the original weight. Each specimen is prepared with a 4 inch square by a thickness of 1.63 inches, and subjected to 50 cycles of freezing and thawing, unless the specimen breaks or appears to have lost more the 1.5% of their original weight. Weight loss is determined as a percentage of the original weight of the dry specimens. The standard deviations of these tests are included in Table V below.
(45) TABLE-US-00005 TABLE V Standard Deviations of Tests Performed. NQ 2624-120 ASTM C666/C666M Cycle 9.4.4.3 Total cycle 5.2 Total cycle time 2 h < duration time 24 h t < 5 h Freezing Thawing duration >25% 16 h +/− 1 h total cycle time Thawing (procedure A) 8 h +/− 1 h Thawing duration >20% total cycle time (procedure B) *Procedure A: rapid freezing and thawing in water Procedure B: rapid freezing in air and thawing in water Temperature 9.4.2.1 5 to −15 deg C. 5.2 4 to −18 deg C. Immersing 9.4.2.6 Salted water Unsalted water liquid * Replaced by fresh water Weight loss 9.4.4 10-25-50 8.3 Intervals not exceeding measurement cycles 36 cycles to reach 300 cycles Means of 9.4.4 Filtering 8.3 Scaling the specimen measuring and scaling itself weight loss particles left in the container
Deco Texturing for DCLV Blocks
(46) In certain embodiments, deep texturing may be included within mold surfaces, as best illustrated in
(47) In certain embodiments, as shown in
(48) By arranging the receded locations and the contact locations within a particular side of the DCLV block strategically, the contract portions of the DCLV are aligned with the imaginary planes and are positioned to contact the contact portions of a mating side of an adjacent DCLV block. Since these contact portions are arranged substantially parallel to the imaginary outer plane, the DCLV blocks may be installed in very straight and level courses that do not require mortar to be applied between courses to achieve a level application.
(49) Installation System for Lightweight Veneer Products
(50) According to certain embodiments of the present invention, a system for installing DCLV block or any other stone or brick veneer blocks that weighs 15 lb/ft.sup.2 or less (collectively, referred to herein as “veneer block”) comprises the use of an air barrier and an adhesive to attach the block to a substrate.
(51) Examples of substrates may include but are not limited to wood, plywood, exterior sheathing, oriented strand board (“OSB”), drywall (also known as plasterboard, wallboard, gypsum board, Sheetrock, Gyproc, plasterboard), chipboard, hardboard, cement board, concrete, blockwork, and fiber cement siding.
(52) In certain embodiments, the air barrier may be any substance used to stop unrestricted air infiltration and exfiltration through a building envelope, which adheres directly to the substrate such that greater than 16 psi of force is required to separate the air barrier from the substrate, as measured according to ASTM D4541. Examples of suitable air barriers that meet these parameters may include but are not limited to ExoAir® 230, which is a fluid-applied vapor-permeable air barrier membrane manufactured by Tremco illbruck.
(53) In certain embodiments, the adhesive may be any substance that provides a high strength flexible bond between the block and the air barrier with a shear strength of approximately 4000-5000 lb/ft.sup.2. The adhesive may be a blend of polymers (including but not limited to acrylic, latex, and urethane polymers) and adhesion promoters, which are compatible with the air barrier composition, and have good adhesion to a variety of construction surfaces including but not limited to brick, concrete, wood, plywood, exterior sheathing, OSB, drywall (also known as plasterboard, wallboard, gypsum board, Sheetrock, Gyproc, plasterboard), chipboard, hardboard, cement board, concrete, blockwork, and fiber cement siding. Furthermore, the adhesive may have an “instant grab” that minimizes the need for additional clamping or other mechanical supports, while still allowing some initial sliding of the block for placement during installation. In addition, the adhesive may have a shore A hardness of at least 50. The adhesive may further have a sufficiently high viscosity that prevents the adhesive from completely flattening when applied in vertical beads to the substrate so as to ensure that a drainage plane between the veneer block and the substrate remains open, as described in more detail below.
(54) Examples of suitable adhesives that meet these parameters may include but are not limited to SP350, which is hybrid polymer sealant and adhesive based on Tremco illbruck's advanced SP hybrid polymer formulation. In other embodiments, the adhesive may be in the form of a tape applied to the cured surface of the air barrier.
(55) In certain embodiments, to install the blocks, the substrate is first treated (or may be pre-treated) with the air barrier.
(56) Once the adhesive has been applied within a section of the substrate, the veneer blocks may be pressed against the adhesive in courses, as best illustrated in
(57) In certain cases, the adhesive installation system is an improvement over conventional installation methods (as described in the background section and shown in
(58) Another advantage is that the skill set needed for the present installation system is not necessarily limited to skilled masons. A painter or other similarly skilled laborer can apply the air barrier to the substrate and apply the adhesive to the cured air barrier surface, as well as adhere courses of veneer blocks to the substrate.
Examples
(59) To test the installation system, wall was constructed with 7-2″×4″×8′ wooden studs secured onto a top and bottom 2″×4″×8′ wood stud plate with 3″ penny nails. As a result, the test area was 5.946 m.sup.2. The wall was then screwed into a 2″×12″ SFP wooden buck. ½″ OSB was then attached horizontally to the exterior with 3″ penny nails spaced approximately every 8″ around the perimeter and 12″ up each stud. The OSB board joint was then detailed with Dymonic 100 polyurethane sealant, then 75 wet-mils of ExoAir 230 air barrier was applied to the exterior. Once the membrane was completely cured, DCLV blocks were attached to the exterior with lines of Tremco illbruck SP350 adhesive spaced approximately every 3″. A starter 2″×4″ wood stud was fastened to the bottom of the buck to prevent the stones from sliding during installation. All sealants and adhesives were allowed to cure, and the 2″×4″ wood stud started was removed before the start of testing.
(60) Tests performed on the wall included: Pre-E2357 air leakage test per E283-1015-001; Wind load conditioning per E2357-1015-002; Post-E2357 air leakage test per E283-1015-003; Deflection test per E2357-1015-004; 15 min 137 Pa water leakage test per E331-1015-005; and 2 hour 300 Pa water leakage test per IBC 1403.2-1015-006.
(61) Test Conditions: Test Temperature at Start (° F.): 67.912; Test Temperature at End (° F.): 69.733; Average Temperature (° F.): 68.492; Avg. Barometric Pressure (in. Hg): 30.415. Water penetration passed 2 hours at 300 Pa (6.27 psf). The air leakage test results are summarized in Table VI below. Additional test results for the air leakage are shown in
(62) TABLE-US-00006 TABLE VI Test Results. Assembly Air Leakage Values @ 75 Pa (1.57 psf) Air Leakage Area Leakage Rate Pre-Conditioning Infiltration 0.04 L/s 0.007 L/s .Math. m.sup.2 (0.09 cfm) (0.001 cfm/ft.sup.2) Pre-Conditioning Exfiltration 0.03 L/s 0.006 L/s .Math. m.sup.2 (0.07 cfm) (0.001 cfm/ft.sup.2) Post-Conditioning Infiltration 0.04 L/s 0.006 L/s .Math. m.sup.2 (0.08 cfm) (0.001 cfm/ft.sup.2) Post-Conditioning Exfiltration 0.04 L/s 0.007 L/s .Math. m.sup.2 (0.09 cfm) (0.001 cfm/ft.sup.2)
(63) Different arrangements of the components depicted in the drawings or described above, as well as components and steps not shown or described are possible. Flexibility in design and construction of components, and of assemblies of components, are among the hallmarks of this invention, so many components and structures in addition to those depicted and described here are possible. Similarly, some features and subcombinations are useful and may be employed without reference to other features and subcombinations. Embodiments of the invention have been described for illustrative and not restrictive purposes, and alternative embodiments will become apparent to readers of this patent. Accordingly, the present invention is not limited to the embodiments described above or depicted in the drawings, and various embodiments and modifications can be made without departing from the scope of the claims below.