The present invention relates generally to materials science, structural construction technology, additive manufacturing techniques, additive construction techniques, compositions for use in construction of structures, and three dimensional (3D) printing. More specifically, mix formulation for 3D printing of Structures is described.
Conventionally, structures such as dwellings, buildings, and sheds are manufactured using a multitude of different materials and construction methods. Among the materials commonly used in the construction of structures is concrete. In conventional examples, concrete may be utilized in the foundation of a structure and possibly in the construction of exterior walls.
Conventionally, Portland cement (OPC) is one of the primary forms of cement used for construction of concrete structures. Portland cement is a fine powder, produced by heating limestone and clay minerals in a kiln to form clinker (primarily calcium silicates (CaO)2-3SiO2, alite Ca3Si and belite Ca2Si), tricalcium aluminate Ca3Al2O4, and tetracalcium aluminoferrite Ca4AlnFe2-nO7), grinding the clinker, and adding 2 to 3 percent of gypsum. However, concrete, Portland cement, mortar, and other conventional compounds are not used as a sole material for the construction of structures due to limitations that can be overcome by using additives, which can create significant and substantial costs.
Thus, what is needed is a structural construction compound without the limitations of conventional techniques.
In some examples, a composition includes an aluminosilicate source and a chemical activator. An exemplary aluminosilicate source may be one or more of rice husk ash, volcanic ash, crushed rocks which are high in alumina content, clays, silica/alumina soils, and shale powder, among others. An exemplary aluminosilicate source may also be one or more of ground granulated blast furnace slag, metakaolin, coal fly ash, bottom ash, municipal solid waste incinerator ash, cement kiln dust, limestone dust, or others.
In some examples, an aluminosilicate source and composition may range from about 10 mass % (i.e., mass %=mass percentage) to about 80 mass % SiO2 and about 2 mass % to about 40 mass % Al2O3. An exemplary composition may include an aggregate such as sand, gravel, crushed stone, or others, without limitation or example. An exemplary aggregate may have a particle size ranging between about 1 mm and about 2 mm. In some examples, an activator element or material may also be used. An exemplary activator may include a base activator such as sodium hydroxide, sodium silicate, or the like, without limitation or restriction. As an example, an exemplary mass ratio of a base activator to an amount of sodium silicate may be between about 1:1 and about 2:1. An exemplary base activator such as sodium silicate may be added, mixed, or otherwise used in solution. In some examples, a concentration of a base activator may be in a range of about 4M (M=moles) to about 14M. An exemplary base activator and an additive such as sodium silicate may also be added to exemplary compounds and compositions, as described herein, may be solids. In some examples, compounds and compositions (hereafter referred to as “compounds” or “compositions”) may include an additive beyond those described herein.
In another example, an exemplary method of forming a structure by additive manufacturing (i.e., additive construction or 3D printing) includes combining a composition above with one or more aggregates to yield a mixture, extruding a first quantity of the mixture through one or more nozzles to form a first layer of the mixture on a substrate, extruding a second quantity of the mixture through one or more nozzles to form a second layer of the mixture on the first layer, and curing the first layer and the second layer to yield the structure.
In some examples, exemplary compositions may include water, which may be combined with a mixture before extruding a first quantity of the combined mixture.
In other examples, a method of forming a structure by additive manufacturing may include combining the above-described materials with water and aggregate to yield a mixture, extruding a first quantity of the mixture through one or more nozzles to form a first layer of the mixture on a substrate (e.g., a foundation), extruding a second quantity of the mixture through one or more nozzles to form a second layer of the mixture on a first layer, and curing the first layer and the second layer to yield the structure.
In some examples, curing a first layer and the second layer may include ultraviolet curing or thermal activation. Curing a first layer and second layer, in some examples, may include bonding the second layer to the first layer and the first layer to the substrate. In some examples, a structure may be an exterior or interior wall, roof, or any other type of structural element or feature, and the substrate may be a foundation. In some examples, one or more nozzles used to extrude mixtures such as those described herein may be heated. An additional amount of an activator material or compound (herein used interchangeably with “activator” may be combined with a mixture at one or more nozzles.
As described herein, exemplary material suitable for construction of structures may be formed from an aluminosilicate source and an alkali activator. Structures may be constructed with or without using Portland cement binders, the latter of which may permit reduction of a carbon footprint in individual construction projections and permit overall carbon emissions to be reduced. In some examples, this may include using structurally strengthened materials such as the above-described mixtures, compounds, and compositions, which can be extruded using additive manufacturing processes to create structures while preserving natural limited resources such as wood, the logging of which can have a deleterious effect by devastating forests and other organic oxygen-producing mechanisms critical to the survival of life on earth. Further, exemplary material may be suitable for construction using a 3D printing process, which may result in increased speed, greatly reduced cost, and greater flexibility for architectural and structural design by creating structural aspects, facets, facades, and other structural, cosmetic, or non-structural elements, without limitation or restriction.
Other elements of the inventive subject matter described herein are further apparent from the following detailed description, figures, and claims.
Various embodiments of the invention are disclosed in the following detailed description and the accompanying drawings:
Like reference numbers and designations in the various drawings indicate like elements, features, functions, or structures.
Various embodiments or examples may be implemented in numerous ways, including as a system, a process, an apparatus, or a composition of matter (i.e., “composition”). In general, operations of disclosed processes may be performed in an arbitrary order, unless otherwise provided in the claims. Compositions of matter may be referred to as “compositions,” which may be created, generated, formed, or otherwise made by combining, in any order unless specified otherwise, different elements, components, material (natural or synthetic), or the like.
A detailed description of one or more examples is provided below along with accompanying figures. The detailed description is provided in connection with such examples, but is not limited to any particular example. The scope is limited only by the claims and numerous alternatives, modifications, and equivalents are encompassed. Numerous specific details are set forth in the following description in order to provide a thorough understanding. These details are provided for the purpose of example and the described techniques may be practiced according to the claims without some or all of these specific details. For clarity, technical material that is known in the technical fields related to the examples has not been described in detail to avoid unnecessarily obscuring the description. Like numbered elements and reference numbers may refer to similar elements despite being described in connection with different drawings. The described techniques may be varied and are not limited to the examples or descriptions provided.
In some examples, compositions of matter such as cement are used for the building, development, or construction (hereafter “construction”) of infrastructure (e.g., buildings, dwellings, homes, houses, commercial office buildings, shelters (on and off-world), roads, bridges, dams, and the like). However, using the techniques and compositions described herein, carbon dioxide emissions can be reduced by limiting the production and use of materials such as Portland cement, which is considered the third-largest producer of CO2 emissions globally, with an estimated 3.5 billion tons of cement made annually accounting, which, by some measures, can account for almost 8-10% of total global carbon dioxide (i.e., CO2) emissions. Thus, non-Portland cementitious binders may be used to reduce carbon dioxide emissions and humankind's overall carbon footprint on the planet (i.e., “earth,” “planet earth,” and “planet” may be used interchangeably hereafter).
In some examples, a composition that includes an aluminosilicate source and uses a process of alkali activation to yield a geopolymer might address these issues. As used herein, “geopolymer” generally refers to an aluminosilicate forming a long-range, covalently bonded, non-crystalline (amorphous) network. Such a composition can be used in a 3D printing apparatus and method to produce a 3D printed structure. Moreover, such a composition can produce a durable and sustainable cementitious binder that can last for years.
The composition 100 also includes aggregate 130, which may include inert granular materials such as sand, gravel, crushed stone, decomposed granite, or others, without limitation or restriction. In some examples, aggregate particle size can range from approximately 1 mm to about 2 mm. Further, in some examples, a mass ratio of aggregate to aluminosilicate source is typically in a range that is substantially between 3:1 and 4:1 (e.g., about 3.5:1). In some examples, aluminosilicate source can vary from approximately 22% to 65% by mass, while the aggregate can vary between approximately 55%-77% by mass.
As described herein, in some examples, aggregate 130 can be provided from natural or waste materials that provide an aluminosilicate source and/or be separately added to composition 100. In some examples, aggregate or similar particulates are removed from an aluminosilicate source so that a base mixture (e.g., binder 110 and chemical activator (“activator”) 120) can be stored in a form substantially without aggregate. In some examples, a base mixture may be stored as a powder to be combined with aggregate 130 and the base mixture (i.e., binder 110 and activator 120) at the time of dispensing. As used herein, “dispensing” may refer to extrusion or the production of a combined mixture (e.g., binder 110, activator 120, and aggregate 130) when, for example, extruded or “printed” using one or more nozzles, as described in greater detail below.
In some examples, activator 120 may be a two-part activator (i.e., include two components, compositions, elements, substances, or the like). As an example, a two-part activator may include a base (e.g., sodium hydroxide) and a sodium silicate (e.g., Na2xSiyO2y+x or (Na2O)x·(SiO2)y, sodium metasilicate (Na2SiO3), sodium orthosilicate (Na2SiO4), sodium pyro silicate (Na6Si2O7), or others, without limit or restriction, including combinations thereof). In other examples, one or both parts of a two-part activator 120 may be in the form of a liquid (e.g., the base (e.g., binder 110 and chemical activator (“activator”) 120) is in solution, sodium silicate is in solution, or a base is in solution and sodium silicate is in solution).
In some examples, an amount of base (e.g., binder 110 and chemical activator (“activator”) 120) can be selected such that a concentration of a base (e.g., binder 110 and chemical activator (“activator”) 120) in the activator is in a range of about 4M to about 14M. In other examples, both parts of a two-part activator may be in the form of a solid. A mass ratio of the base to the sodium silicate is typically in a range between approximately 1:1 to approximately 2:1. Other types of activators include potassium and bromide based activators. In some examples, an activator (e.g., sodium hydroxide) may be extracted from waste materials such as brine, which may be a by-product of saline. In other examples, an activator for additive manufacturing, additive construction, or a 3D printable geopolymer system for extruding structural construction material can be obtained from waste glass and rice husk ash.
In other examples, one or more additives 140 can be combined with composition 100 or the base mixture. Additives, as an example, may be added to change, modify, add, delete, improve, lessen, greaten, or otherwise affect chemical composition and/or structural properties of material to be extruded in an additive manufacturing, additive construction, or 3D printing system. For example, to make a binder for 3D printing applications, in some examples, a superplasticizer (polycarboxylate ether (PCE), air entrainer, and a viscosity modifier can be combined with a composition or base mixture. In another example, a polymeric additive may be used to enhance the material and/or structural strength of an interlayer bond between printed layers extruded by an additive manufacturing, additive construction, or 3D printing system such as those described herein, without limitation or restriction. In still other examples, accelerators may be added for combination into a mixture (e.g., base, or otherwise).
Referring back to
In some examples, construction system 10 includes rail assemblies 20, each of which may be configured to include tread 20a and track 20b. In some examples, tread 20a may be laid or withdrawn within track 20b using electrical motors and gearing (not shown) that are driven by drive assemblies (not shown) to “pick up” or “lay down” treads 20a. For vertical displacement of printing assembly 90, drive assembly 60 may be implemented to vertically raise or lower printing assembly by using, for example, a screw or worm-type drive mechanism that raises and lowers support 80, which includes horizontal drive assemblies and mechanisms for moving printing assembly 90 in a substantially horizontal direction (in conjunction with vertical movement using drive assembly 60). Gantry 50, moving along rails 20 while printing assembly 100 is raised and lowered can be used to print structure 5 by extruding compositions (such as those described above) to print walls 7 with windows 3 and doors 9 formed by ceasing extrusion while printing based on a pattern that is provided in the form of control signals from control and power unit 209 to printing assembly 90 and drive assembly 60. In some examples, control and power unit may be configured with firmware, software, or circuitry that is used to control gantry 50 to position printing assembly 100 to print structure 5 or, in other examples, different structures beyond the ones that are shown and described.
In some examples, printing assembly 100 may be configured to be movably disposed on rail assemblies 20a-20b, 60 and 66, with drive assemblies 42 and 87 being used to manipulate positioning of one or more nozzles (not shown) in printing assembly 100, which is designed, configured, and positioned in three dimensions along vertical and horizontal axes (i.e., to position printing assembly 100 in three dimensions consistent with axes 12, 14, and 16) to extrude mixture 150 (
In some examples, printing assembly 100 may be configured to be movably disposed on rail assemblies 20a-20b, 60 and 66, with drive assemblies 42 and 87 being used to manipulate positioning of one or more nozzles (not shown) in printing assembly 100, which is designed, configured, and positioned in three dimensions along vertical and horizontal axes (i.e., to position printing assembly 100 in three dimensions consistent with axes 12, 14, and 16) to extrude mixture 150 (
Referring to
As shown, printing assembly 90 movably disposed on gantry 50. As an example, construction system 10 may be configured to form (e.g., print, extrude material to form or shape, or the like) structure 5 using compositions such as those described above in connection with
As shown in
By selectively dispensing the mixture 150 (
In some examples, heat curing may help activate a polymeric matrix (i.e., within mixture 150 (
For example, curing may be performed using thermal activation by heating extruded layers as mixture passes through a nozzle (not shown). In other examples, curing may be performed when mixture (i.e., a composition of a combined mixture of aluminosilicate, activator, and aggregate) is extruded from a nozzle (not shown) of printing assembly 90 (
Although the description above has focused on 3D printing of structures, geopolymer compositions such as those described herein can also be used with other additive manufacturing, additive construction, or 3D printing systems. Further, compositions such as those described above may also be used with conventional construction techniques (e.g., pouring into a mold) by displacing the use of other materials (e.g., Portland cement), equipment, and systems, without limitation or restriction.
A number of embodiments of the invention have been described. It will be understood that various modifications may be made without departing from the spirit and scope of the invention. Although the foregoing examples have been described in some detail for purposes of clarity of understanding, the invention is not limited to the details provided. There are many alternative ways of implementing the inventive subject matter. The disclosed examples are illustrative and not restrictive.
This nonprovisional patent application claims the benefit of copending U.S. Provisional Patent Application No. 63/289,547, filed Dec. 14, 2021 and titled, “MIX FORMULATION FOR 3D PRINTING OF STRUCTURES,” all of which is herein incorporated by reference in its entirety for all purposes.
Number | Date | Country | |
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63289547 | Dec 2021 | US |