FIELD OF THE INVENTION

[0001] The present disclosure pertains generally to hemp concrete. More specifically, the present disclosure is directed to a self-curing concrete composition comprising hemp hurds, aggregates, cement as binder and water. The present disclosure also relates to a process of preparing said composition.
BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art. [0003] Concrete is a composite material composed of binders, fillers, water and aggregates. Aggregates include both fine and coarse chunks of material like gravel, limestone etc. which are mostly sourced from nature. Continuous mining of these resources causes land erosion as well as loss of biodiversity. With increase of the hydrating degree of various clinker minerals in cement particles, gels grow and capillary porosities decrease, which increases the strength of concrete as it ages. It is proven that cement develops rapidly within 28 days and slowly after 28 days. During this hydration process lot of water is needed to cure the concrete otherwise it develops cracks on its surface upon setting. However, it may not always be feasible to make available such high quantities of water. Ordinary concrete also has the problem of negligible to zero thermal insulation, thus houses made with them have extreme temperatures, i.e., too cold in winters and too hot in summers. [0004] Plant based aggregates are looked at as an alternate option to mineral aggregates. Hemp a fast-growing variety of cannabis which has been used in concrete since ages. The hemp leaves, seeds and fiber have been used for various purposes but hemp hurd (shiv) is generally thrown or burnt. Incorporation of hemp hurds in concrete preparation is an effective way to provide an optimum utilization of agro-waste.
[0005] Some of articles report the hemp based concrete (hempcrete) which are essentially made of hemp hurd, lime (hydraulic lime, powdered limestone) and

water to arrive at the product having insulation properties, e.g. "The Amazing World of Hemp: Hempcrete - the Most Sustainable Building Material on Earth" (Zoe Biehl, CannabisTech, 13 May 2019); "Some Interesting Facts About Hempcrete As a Building Material" (Dave Burkey et al., Hemp News, Manufacturing News, 30 March 2016); and "Hemp MythBusters — Can hempcrete replace concrete?" (Taylor Woods, 03 Sep 2019). However, these articles essentially convey to use lime as binder and provide disadvantages of cement as binder. Also, the lime is available in the impure form and can generate the problems of gaining strength by concrete in required time. Additionally, these articles require higher amounts of water for curing of the concrete (as discussed above). Accordingly, these articles fail to provide optimum proportions of hemp hurd, cement and water containing composition which has advanced effects like self-curing nature which require very low water for the curing and accordingly, cost efficient in the overall production.
[0006] Previous research efforts and achievements notwithstanding, there is a continuing need to develop the concrete composition comprising specific amounts of hemp hurds, aggregates, cement as binder and water, which has self-curing, better insulation and crack resistance properties. The present disclosure also provides curing by using minimal amounts of water making the concrete composition cost effective. Accordingly, the present disclosure satisfies the existing needs, as well as others, and generally overcomes the deficiencies found in the prior art.
[0007] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.

OBJECTIVES OF THE INVENTION
[0008] An object of the present disclosure is to provide a hemp concrete
composition that overcomes the deficiencies known in the art.
[0009] An object of the present disclosure is to provide a hemp concrete
composition that is self-curing and does not require excess water.
[0010] An object of the present disclosure is to provide a hemp concrete
composition that is crack resistant.
[0011] An object of the present disclosure is to provide a self-curing concrete
composition as an alternative to ordinary concrete.
[0012] An object of the present disclosure is to provide a self-curing hemp concrete
composition that is light weight and more useful in hot and humid climate having
better insulation properties.
SUMMARY OF THE INVENTION
[0013] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in Detailed Description section. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
[0014] The present disclosure relates to a novel concrete composition containing hemp hurds, with advantageous effects of self-curing, improved crack resistant and better insulation in different climates. The hemp hurds specifically obtained from hemp plant which is an industrial variety of Cannabis sativa plant species grown for its fiber content or seeds. The Cannabis sativa is a wild shrub and found in most part of the north Indian regions (locally known as Bhang). The hemp hurds may be considered an agro-waste that are utilized in the present disclosure and thus, the disclosure converts waste into useful materials.
[0015] Accordingly, in one aspect the present disclosure provides a self-curing concrete composition comprising hemp hurds, a binder, aggregate and water. [0016] In an embodiment, the binder may be selected from cement, lime, bitumen, natural fibers, clay, combinations thereof and the like.

[0017] In an embodiment, the aggregates may be selected from crusher site, river
bed and the like.
[0018] In an embodiment, the composition requires very minimal amount of water
(around 20 % of normal curing water in case of normal concrete) for curing, thus,
it is self-curing and saves water.
[0019] In another aspect, the present disclosure relates to a process of preparing a
self-curing concrete composition comprising hemp hurds.
[0020] Other aspects of the invention will be set forth in the description which
follows, and in part will be apparent from the description, or may be learnt by the
practice of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0021] The following is a detailed description of embodiments of the disclosure. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0022] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[0023] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or

characteristics may be combined in any suitable manner in one or more
embodiments.
[0024] In some embodiments, numbers have been used for quantifying weights,
percentages, ratios and so forth, to describe and claim certain embodiments of the
invention and are to be understood as being modified in some instances by the term
"about." Accordingly, in some embodiments, the numerical parameters set forth in
the written description and attached claims are approximations that can vary
depending upon the desired properties sought to be obtained by a particular
embodiment. In some embodiments, the numerical parameters should be construed
in light of the number of reported significant digits and by applying ordinary
rounding techniques. Notwithstanding that the numerical ranges and parameters
setting forth the broad scope of some embodiments of the invention are
approximations, the numerical values set forth in the specific examples are reported
as precisely as practicable. The numerical values presented in some embodiments
of the invention may contain certain errors necessarily resulting from the standard
deviation found in their respective testing measurements.
[0025] Various terms as used herein are shown below. To the extent a term used in
a claim is not defined below, it should be given the broadest definition persons in
the pertinent art have given that term as reflected in printed publications and issued
patents at the time of filing.
[0026] As used in the description herein and throughout the claims that follow, the
meaning of "a," "an," and "the" includes plural reference unless the context clearly
dictates otherwise. Also, as used in the description herein, the meaning of "in"
includes "in" and "on" unless the context clearly dictates otherwise.
[0027] Unless the context requires otherwise, throughout the specification which
follow, the word "comprise" and variations thereof, such as, "comprises" and
"comprising" are to be construed in an open, inclusive sense that is as "including,
but not limited to."
[0028] The recitation of ranges of values herein is merely intended to serve as a
shorthand method of referring individually to each separate value falling within the

range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein.
[0029] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. "such as") provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0030] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified.
[0031] The description that follows, and the embodiments described therein, is provided by way of illustration of an example, or examples, of particular embodiments of the principles and aspects of the present disclosure. These examples are provided for the purposes of explanation, and not of limitation, of those principles and of the disclosure.
[0032] It should also be appreciated that the present disclosure can be implemented in numerous ways, including as a system, a method, or a device. In this specification, these implementations, or any other form that the invention may take, may be referred to as processes. In general, the order of the steps of the disclosed processes may be altered within the scope of the invention.
[0033] The headings and abstract of the invention provided herein are for convenience only and do not interpret the scope or meaning of the embodiments. [0034] The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to

include all possible combinations of the disclosed elements. Thus, if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed. [0035] The present disclosure provides a sustainable, self-curing concrete composition comprising hemp hurds. It has a range of desirable thermal and structural properties that make it a green alternative to ordinary concrete. Self-curing hempcrete offers an alternative sustainable option for constructions of massive buildings and structures where exposure of the interiors of the structure to air for curing is minimal.
[0036] Thus, one aspect of the present disclosure provides a self-curing concrete composition comprising hemp hurds, a binder, aggregate and water. [0037] Hemp is a variety of the Cannabis sativa plant species that is grown specifically for the industrial uses of its derived products. It is one of the fastest growing plants and was one of the first plants to be spun into usable fiber 50,000 years ago. It can be refined into a variety of commercial items, including paper, textiles, clothing, biodegradable plastics, paint, insulation, bio-fuel, food, and animal feed.
[0038] While any suitable binder may be employed in the concrete composition according to the present disclosure, preferably, the binder may be selected from cement, lime, bitumen, natural fibers, clay, combinations thereof and the like. More preferably, the binder is cement, selected from but not limited to ordinary Portland cement, Pozzolanic cement and the like. The cement availability is very easy compared to other binders.
[0039] While any suitable aggregate may be employed in the concrete composition according to the present disclosure, preferably, the aggregates are either coarse aggregate or fine aggregate. In an embodiment, the aggregates may be selected from crusher mix, river bed and the like.
[0040] In an embodiment, the composition may comprise of hemp hurds in the weight range of about 2 % to about 90 % by weight of the composition. In another embodiment, the composition may comprise hemp hurds in the weight range of

about 3% to about 40%, about 4% to about 30%, or about 5% to about 10% by
weight of the composition.
[0041] In an embodiment, the composition may comprise of binder in the weight
range of about 2% to about 90% by weight of the composition. In another
embodiment, the composition may comprise binders in the weight range of about
5% to about 70%, about 10% to about 50%, or about 15% to about 20% by weight
of the composition.
[0042] In an embodiment, the composition may comprise of aggregate in the weight
range of about 20% to about 90% by weight of the composition. In another
embodiment, the composition may comprise aggregate in the weight range of about
30%) to about 80%), more preferably about 40% to about 70%, or about 50% to about
55%) by weight of the composition.
[0043] In an embodiment, the composition may comprise of water in the weight
range of about 1% to about 50% by weight of the composition. In another
embodiment, the composition may comprise water in the weight range of about 5%
to about 40%, about 10% to about 30%, or about 15% to about 20% by weight of
the composition. In an embodiment, the amount of water used may be minimal.
[0044] In a preferred embodiment, the composition may comprise concrete hemp
hurds present in a weight range of about 5% to about 10%; cement as binder present
in a weight range of about 15% to about 20%; aggregate present in a range of about
50%) to about 55%; and water present in a weight range of about 15% to about 20%.
[0045] In another embodiment, the composition may further comprise fillers or
additives, well known in the art of cement manufacturing.
[0046] In another preferred embodiment, the composition may comprise cement,
coarse aggregate, hemp hurd, fine aggregate and Alccofine in a ratio of about 0.9:
1.9:0.1:4:0.1.
[0047] In yet another preferred embodiment, the composition may comprise
cement, fine aggregate, hemp hurd and Alccofine in ratio of about 0.9: 2.7: 0.3: 0.1.
[0048] In an embodiment, the self-curing concrete composition may be used to
prepare bricks, walls, slabs, ceilings, panels, blocks, hollow blocks,
external/internal plasters or similar structural components. These components may

be used in construction of houses, buildings or public work. Said concrete can cover
a range of applications and utilizations. In a particular embodiment, the composition
may be used for mass constructions in hot and water scarce regions.
[0049] As employed herein, the terms "internal curing" or "self-curing" relate to a
process by which curing takes place from inside to outside, the hydration of cement
occurs because of presence of internal water without mixing water. Generally, the
concrete requires higher amounts of water for curing which would not be cost
effective on industrial level and the present disclosure solves this problem by
providing self-curing, cost effective concrete composition.
[0050] As employed herein, the term "aggregate" relate to a broad category of
coarse- to medium-grained particulate material used in construction, including
sand, gravel, crushed stone, slag, recycled concrete and geosynthetic aggregates.
[0051] As employed herein, the terms "hemp hurds" or "shives" relate to the
wooden inner parts of the hemp stalk, which are first broken into fragments and
separated from the fiber by way of breaking and scutching.
[0052] In another embodiment, the composition requires minimum amount of water
for curing thus, it is self-curing and preserves water. In a preferred embodiment,
less than 20% of water maybe required for the production of concrete composition.
It is suitable for hot, humid and water-scarce regions.
[0053] In various embodiments, the composition disclosed herein uses hemp which
has a negative carbon footprint and utilizes hemp hurds which are agro-waste. It
minimizes the amount of carbon emissions and energy demands observed during
ordinary concrete production. Thus, the present disclosure provides an inexpensive,
recyclable and ecological alternative construction material.
[0054] In the ordinary concrete, cracks develop on the surface after sometime due
to heat of hydration of cement and improper curing. The concrete composition
disclosed herein does not crack or shrink after the concrete sets, as it contains hemp
fibers which may act as crack retarders.
[0055] In various embodiments, the hemp hurd added in the concrete composition
absorbs water from atmosphere and concrete thus made remain damp for few days.

This property decreases the water requirement for curing of concrete made using
hemp hurd.
In various embodiments, the present disclosure provides self-curing compositions
in which around 10% of coarse and fine aggregate is being replaced with the hemp
hurd, which is a waste industrial material and normally available for free of cost.
Hence, the cost of curing concrete / mortar surface will be reduced to half. In
overall, it may decrease the cost of construction by around 8%.
[0056] In various embodiments, the composition disclosed herein is much lighter
than ordinary concrete thereby decreasing construction costs.
[0057] In various embodiments, the present disclosure provides a self-curing
concrete composition that absorbs carbon dioxide from the environment and is thus
a green sustainable alternative to normal concrete.
[0058] In various embodiments, the composition disclosed herein possesses lower
thermal insulation compared to ordinary concrete. Thus, there will be a temperature
difference in the buildings and houses constructed using the present concrete and
constructed using normal concrete.
[0059] In various embodiments, the desired properties of the concrete composition
disclosed herein may be developed by maintenance of a satisfactory moisture
content and temperature in the concrete for a suitable period of time immediately
following placing & finishing.
[0060] In an embodiment, the present disclosure relates to a process of preparing a
self-curing concrete composition.
[0061] In another embodiment, the present disclosure provides a process for the
preparation of self-curing concrete composition, the process comprising the steps
of:
collecting, drying, crushing and grinding hemp hurds in the heavy duty mixture;
and
mixing dried powdered hemp hurd, aggregates, binder and water in vibration
machine to obtain the self-curing composition;
optionally, curing the composition using minimal amount of water.

[0062] In another embodiment, the process described herein uses the minimal amount of water for curing which is at most 20 wt%, preferably in the range of about 5 to 20 wt% or about 10 to 20 wt% or about 15 to 20 wt%. [0063] In another embodiment, hemp hurds may be mixed in the dry state with aggregates thoroughly before adding the mix in the binder and water. [0064] While the foregoing describes various embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art. EXAMPLES
[0065] The present disclosure is further explained in the form of following examples. However, it is to be understood that the foregoing examples are merely illustrative and are not to be taken as limitations upon the scope of the invention. Various changes and modifications to the disclosed embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the scope of the invention. EXAMPLE 1
The concrete mix composition recites amount of cement, coarse and fine aggregates, hemp hurd, alccofine and water as provided in below table 1. Table 1: Amount of components in Concrete mix composition

Composition Components Quantities for Concrete mix (for one cubic meter of concrete)
Concrete Mix Cement 313.33 kg

Coarse aggregate 1081.1 kg at 0.8% moisture 20 mm - 540.55 kg 10 mm-540.55 kg

Hemp hurd 120 kg

Fine aggregate 651.24 kg at 1.8% moisture

Alccofine 34.8 kg

Water 191.58 kg
EXAMPLE 2
The composition provided in example 1 is prepared by collecting hemp hurd from the plant Cannabis sativa, then oven dried, crushed and grinded in the heavy duty mixtures. Then, 120 kg of dried powdered hemp hurd, 313 kg of cement, 1081 kg of coarse aggregate, 191.58 kg of fine aggregate and 34.8 kg of alccofine are mixed together or simultaneously in the laboratory in the vibration machine to obtain a concrete composition containing sufficient amount of about 50 wt% of moisture. Finally, the composition is cured by using 50% of water which is actually required for curing the normal concrete and thereafter, the cured composition is tested in Universal Testing Machine for determining its compressive strength. A 28 days-compressive strength of said designed concrete mix composition was 22 MPa. EXAMPLE 3
The mortar mix composition recites specific amount of cement, fine aggregate, hemp hurd, alccofine and water as provided in below Table 2.
Table 2: Amount of components in Mortar mix Composition

Composition Components Quantities for mortar mix (for one cubic meter of mortar)
Mortar mix Cement 450 kg

Fine aggregate 1485 kg

Hemp hurd 15 kg

Alccofine 50 kg

Water 250 kg
EXAMPLE 4
The composition provided in example 3 is prepared by collecting hemp hurd from the plant Cannabis sativa, oven dried, and then crushed and grinded in the heavy

duty mixtures. Thereafter, 15 kg of dried powdered hemp hurd, 450 kg of cement, 1485 kg of fine aggregate and 50 kg of alccofine are mixed together or simultaneously in the laboratory in the vibration machine to obtain a mortar composition containing sufficient amount of moisture about 50%. Finally, the composition is cured by using 50% of water which actually required for curing of mortar without hemp and thereafter, the cured composition is tested on Universal Testing Machine for determining its compressive strength. The compressive strength of this mortar mix was 10 MPa.
According to above examples, the present disclosure provides self-curing compositions in which around 10% of coarse and fine aggregate is being replaced with the hemp hurd, which is a waste industrial material and normally available for free. Hence, the cost of curing concrete / mortar surface will be reduced to half. In overall, it may decrease the cost of construction by around 8%.
ADVANTAGES OF THE INVENTION
[0066] The present disclosure provides a self-curing concrete composition that
overcomes the deficiencies of known arts.
[0067] The present disclosure provides a self-curing concrete composition that is
economical and utilizes waste hemp materials.
[0068] The present disclosure provides a self-curing concrete composition that
absorbs carbon dioxide from the environment and is thus a green alternative to
concrete.
[0069] The present disclosure provides a self-curing concrete composition that is
light and crack resistant.
[0070] The present disclosure provides a self-curing concrete composition suitable
for mass concreting.

We Claim:

1. A self-curing concrete composition comprising:
hemp hurds,
a binder, aggregates, and water.
2. The self-curing concrete composition as claimed in claim 1, wherein the binder is selected from the group consisting of cement, lime, bitumen, natural fibers, clay or combinations thereof.
3. The self-curing concrete composition as claimed in claim 1 or 2, wherein the binder is cement.
4. The self-curing concrete composition as claimed in claim 3, wherein the cement is selected from ordinary Portland cement or Pozzolanic cement.
5. The self-curing concrete composition as claimed in claim 1, wherein the aggregate is crusher mix or river bed.
6. The self-curing concrete composition as claimed in claim 1, wherein the hemp hurds is in the weight range of about 2 % to about 90 % by weight of the composition.
7. The self-curing concrete composition as claimed in claim 1 or 6, wherein the hemp hurds is in the weight range of about 3% to about 40%, or about 4% to about 30%, or about 5% to about 10% by weight of the composition.
8. The self-curing concrete composition as claimed in any one of preceding claims 1-4, wherein the binder is in the weight range of about 2% to about 90%) by weight of the composition.
9. The self-curing concrete composition as claimed in any one of preceding claims 1-4 and 8, the binder is in the weight range of about 5% to about 70%, about 10% to about 50%, or about 15% to about 20% by weight of the composition.

10. The self-curing concrete composition as claimed in claim 1 or 5, the aggregate is in the weight range of about 20% to about 90% by weight of the composition.
11. The self-curing concrete composition as claimed in any one of preceding claims 1, 5 and 10, wherein the aggregate is in the weight range of about 30% to about 80%, or about 40% to about 70%, or about 50% to about 55% by weight of the composition.
12. The self-curing concrete composition as claimed in claim 1, wherein the water is in the weight range of about 1% to about 50% by weight of the composition.
13. The self-curing concrete composition as claimed in claim 1 or 12, wherein the water is in the weight range of about 5% to about 40%, or about 10% to about 30%, or about 15% to about 20% by weight of the composition.
14. The self-curing concrete composition as claimed in claim 1, further comprises fillers or additives.
15. A process for the preparation of self-curing concrete composition as claimed in claim 1, the process comprising the steps of:
collecting, drying, crushing and grinding hemp hurds in a heavy duty
mixture; and
mixing dried powdered hemp hurd, aggregates, binder and water in
vibration machine to obtain the self-curing composition;
optionally, curing the composition using minimal amount of water.
16. The process as claimed in claim 15, wherein the minimal amount of water
for curing is at most 20 wt%.