Description:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
METHOD OF PROCESSING CONSTRUCTION AND DEMOLITION WASTE

Applicant(s):
DEBRIES SOLUTION PRIVATE LIMITED.
An Indian company having address as:
Unit 603 Quantum Towers, Off S.V. Road, Malad West Rambaug, Mumbai, Maharashtra, India-400064

The following specification describes the invention and the manner in which it is to be performed

PRIORITY INFORMATION
[001] The present application does not claim a priority from any other application.
FIELD OF INVENTION
[002] The present invention relates to processing of construction and demolition waste.
BACKGROUND
[003] Construction and Demolition (C&D) waste refers to waste generated from partial or complete demolition or repairing/renovation of various manmade structures, such as buildings, dams, bridges, piers and roadworks. The C&D waste contains a wide variety of materials such as concrete, bricks, wood, glass, metals, earth, rock, rubble, steel, reinforcement, mortar, plaster, tiles, and gypsum. Only a very tiny portion of the entire C&D waste generated each year is recycled or processed and rest is dumped on lands, and this creates huge landfills.
[004] Thus, safe and environment friendly disposal of the C&D waste has become a major challenge, and a method enabling the same is much desired.
SUMMARY
[005] Before the present method for processing construction and demolition waste is described, it is to be understood that this application is not limited to the particular systems, and methodologies described, as there can be multiple possible embodiments which are not expressly illustrated in the present disclosures. It is also to be understood that the terminology used in the description is for the purpose of describing the particular implementations or versions or embodiments only, and is not intended to limit the scope of the present application.
[006] This summary is provided to introduce aspects related to a method for processing construction and demolition waste. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.
[007] In one implementation, a method for processing construction and demolition waste is described. The method comprises receiving the construction and demolition waste. The method further comprises segregating an undesired material from the construction and demolition waste to obtain a filtered residue. The filtered residue comprises brick, mortar, plaster, and concrete. The method further comprises grinding the filtered residue to obtain a crushed material having a maximum particle size of up to 12mm. The method further comprises preparing a construction mixture by mixing the crushed material with a binding material in a predetermined ratio.
[008] In one aspect, the predetermined ratio of the crushed material used for preparing the construction mixture is present in a range of 60% to 95% by weight.
[009] In one aspect, the binding material is cement.
[0010] In one aspect, the predetermined ratio of the binding material used for preparing the construction mixture is present in a range of 5% to 40% by weight.
[0011] In one aspect, grinding of the filtered residue is carried by a crushing machine.
[0012] In one aspect, a portion of the crushed material having a size greater than the maximum particle size is segregated, and such portion of the crushed material is grinded to obtain the maximum particle size of up to 12mm.
[0013] In one aspect, the undesired material segregated from the construction and demolition waste comprises one or more of earth, wood, metal, plastic, rock, rubble, steel, reinforcement, brick, mortar, plaster, tiles, and concrete.
[0014] In one aspect, the crushed material is separated into a coarse aggregate of particle size ranging from 4.75-12mm and a fine aggregate of particle size ranging below 4.75mm.
[0015] In one aspect, construction blocks are created using the construction mixture made out of the C&D waste. The construction blocks are one of perforated blocks, solid blocks, hollow blocks, aerated autoclaved blocks, bricks, paver blocks, lintel blocks, stretcher blocks, corner blocks, pillar blocks, jamb blocks, partition blocks, frogged brick blocks, and bullnose blocks.
[0016] In one aspect, the construction blocks are cured in a humid environment.
[0017] In one aspect, the construction mixture is prepared using 20% - 40% coarse aggregate and 60% - 80% fine aggregate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The accompanying drawings constitute a part of the description and are used to provide further understanding of the present disclosure. Such accompanying drawings illustrate the embodiments of the present disclosure which are used to describe the principles of the present disclosure. The embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and they mean at least one. In the drawings:
[0019] Figs. 1a and 1b cumulatively illustrate a system for processing a construction and demolition waste, in accordance with an embodiment of the present disclosure;
[0020] Fig. 2 illustrates table providing different manufacturing and strength parameters related to hollow blocks, in accordance with an embodiment of the present disclosure; and
[0021] Fig. 3 illustrates a flow chart of a method for processing construction and demolition waste, in accordance with an embodiment of the present subject matter.
DETAILED DESCRIPTION OF THE INVENTION
[0022] Present invention describes a method of recycling of Construction and Demolition (C&D) waste. The method starts with receiving the C&D waste at a recycling facility. The C&D waste is then sorted and graded to remove any contaminants and separate different types of materials such as concrete, steel, wood, plastic, and metal. Once graded, the C&D waste is crushed in a jaw crusher for obtaining a crushed material having smaller pieces. The crushed material is similar to fine sand. A flywheel is used to adjust a maximum particle size of the crushed material. Any pieces larger than the maximum particle size are filtered out using a screening process. The process of crushing and filtering is repeated until 100% of the C&D waste obtains the maximum particle size desired. A mixture of the crushed material and a binding material is then used as a construction material for a variety of applications, including preparation of construction blocks.
[0023] Referring now to Figs. 1a and 1b, a system for processing a C&D waste 100 is explained. The C&D waste 100 may be received from one or more construction or demolition sites, by a suitable mean, such as a truck 102. The C&D waste 100 may include several types of materials, such as mud, wood, metal, plastic, brick, mortar, plaster, and concrete. An undesired material 104 is segregated from the C&D waste 100 to obtain a filtered residue 106. The undesired material 104 may comprise earth, wood, metal, plastic, rock, rubble, steel, reinforcement, brick, mortar, plaster, tiles, and concrete. The filtered residue 106 may comprise brick, mortar, plaster, and concrete. The undesired material 104 may be segregated from the C&D waste 100 using one or more of magnet, air, and water based separating machines.
[0024] In one scenario, a magnet based separating machine 108 may be used for segregating the undesired material 104 (metallic pieces) from the C&D waste 100, for obtaining the filtered residue 106. The magnet based separating machine 108 includes a rotating drum 110 with magnets 112 arranged in its centre. During operation of the magnet based separating machine 108, the rotating drum 110 may rotate in a particular direction, for example in an anti-clockwise direction. With rotation of the rotating drum 110, the undesired material 104 (metallic pieces) are carried and released at a location different from a location of release of the filtered residue 106 which gets separated under the effect of gravity.
[0025] Thereafter, the filtered residue 106 is grinded to obtain a crushed material 114. The crushed material 114 may have a maximum particle size of up to12mm. Grinding of the filtered residue 106 may be carried by a crushing machine 116 that may be pneumatically or hydraulically operated. In one implementation, the crushing machine 116 may include two rollers 118 (118-1, 118-2) configured to rotate in opposite directions. A first roller 118-1 may be fixed in a particular position and a second roller 118-2 may be pushed towards the first roller 118-1 by a compression spring 120 having desired compressive strength. With rotation of the two rollers 118 and the second roller 118-2 pushing towards the first roller 118-1, the filtered residue 106 may be grinded to obtain the crushed material 114. The compressive strength of the compression spring 120 may be one parameter responsible for obtaining the maximum particle size of the crushed material 114.
[0026] In some embodiments, the filtered residue 106 may be grinded at one or more stages. For example, when it is determined that a portion of the crushed material 114 has a size greater than the maximum particle size, the portion of the crushed material 114 may be segregated, for example through vibration screening and transferred back to the crushing machine 116 for grinding. The portion of the crushed material 114 may be transferred to the crushing machine 116 through a conveyor, such as a belt conveyor. In this manner, grinding of the filtered residue 106 is performed until whole of the crushed material 114 has obtained the maximum particle size of up to12mm.
[0027] Thereafter, the crushed material 114 may be separated into a coarse aggregate 122 and a fine aggregate 124. The coarse aggregate 122 may have a particle size ranging from 4.75mm - 12mm and the fine aggregate 124 may have a particle size ranging up to 4.75mm. In one implementation, the crushed material 114 may be separated into the coarse aggregate 122 and the fine aggregate 124 using a sieving machine 126. The sieving machine 126 may include a screening layer 128 having pores of a size sufficient to pass through only the fine aggregate 124. To pass through the fine aggregate 124 having the particle size ranging up to 4.75mm, the size of the pores present on the screening layer may be 4.75mm. To filter the fine aggregate 124, the screening layer 128 may be vibrated/agitated at a particular frequency. Post filtering of the screening layer 128, the coarse aggregate 122 may be left behind and collected at a separate location.
[0028] Thereafter, different concentrations of the coarse aggregate 122 and the fine aggregate 124 may be mixed together to prepare a construction mixture 130, in a mixing unit 132. In one preferred implementation, 20%-40% of the coarse aggregate 122 and 60% - 80% of the fine aggregate 124 may be used for development of a construction mixture 130.
[0029] Additionally, a binding material 134, such as cement may be mixed in a predetermined ratio in the crushed material 114 to prepare the construction 130. The mixing may be performed in the mixing unit 132. The crushed material 114 and the binding material 134 may be mixed by the mixing unit 132. The predetermined ratio of the crushed material 114 used for preparing the construction mixture 130 may be present in a range of 60% to 95% by weight. Further, the predetermined ratio of the binding material 134 used for preparing the construction mixture 130 may be present in a range of 5% to 40% by weight.
[0030] The construction mixture 130 may be used to prepare construction blocks, such as hollow blocks. For development of the hollow blocks, the construction mixture may be mixed with water 136, in a mixing unit 138, to form a mixture 140. The mixture 140 may be collected in a storage unit 142 or a feeder unit and thereupon transferred to a block manufacturing machine. The block manufacturing machine may pour the mixture 140 into moulds having a hollow cavity in centre. The moulds may be made of metal or plastic, and their size and shape can vary depending on desired size and shape of the blocks. Thereafter, the hollow blocks are left to cure in a humid atmosphere for a specific period, such as 28 days. This allows the mixture 140 to set and harden, resulting in strong and durable hollow blocks.
[0031] Once the hollow blocks are removed from the mould. they are stacked and left to air-dry for a few days for further strengthening and curing. Thereafter, the hollow blocks may be finished by trimming off any excess material, smoothing rough edges, and sanding of surfaces if necessary.
[0032] In each construction block, the binding material and the crushed material may be used in a ratio varying from 1:6 to 1:7. Further, 0.5-0.6% weight of each construction block may be composed of water.
[0033] In one implementation, each construction block may weigh about 15 to 20 kg. A construction block weighing 19kg may have the composition mentioned in below provided Table 1.
Table 1
Weight of construction block Composition of crushed material Composition of binding material
19kg 16.1kg 2.9 Kg
Composition of coarse aggregate Composition of fine aggregate
4.03 Kg 12.07 Kg

[0034] Although the process of development of hollow blocks is described above, other types of construction blocks such as perforated blocks, solid blocks, aerated autoclaved blocks, bricks, paver blocks, lintel blocks, stretcher blocks, corner blocks, pillar blocks, jamb blocks, partition blocks, frogged brick blocks, and bullnose blocks may be developed in a similar manner. Further, the above described methodology could be used for development of other building blocks or complete structures different than the construction blocks.
[0035] Alternatively, the construction mixture made out of C&D waste may be used by 3D printer for development of a physical structure, for example a water tank. The 3D printer may deposit the mixture in a layer wise manner based on a 3D model of the structure required to be developed, such as a 3D model of water tank.
[0036] Fig. 2 illustrates a table providing different manufacturing and strength parameters related to hollow blocks. Specifically, compressive strengths of hollow blocks casted using C&D waste is provided. The compressive strengths were determined at 7 and 28 days for hollow block samples A1 through D3. For instance, upon application of a load of 209kN on a hollow block sample A1 having a binder to aggregate ratio of 1:6 and a water to binder ratio of 0.50, 7 days’ compressive strength was determined to be 2.58MPa. Further, 7 days’ average compressive strength of 2.58MPa was determined upon application of different loads on multiple such hollow block samples having same binder to aggregate ratio and water to binder ratio. Further, upon application of a load of 295.3kN on the hollow block sample A1, 28 days’ compressive strength was determined to be 3.65MPa, and 28 days’ average compressive strength of 3.64MPa was determined upon application of different loads on multiple such hollow block samples. By performing such tests on multiple hollow block samples, a minimum compressive strength at 28 days as per IS 2185: part 1 was determined to be 3.5MPa.
[0037] Dry density determined at 28 days for samples of hollow blocks cast with the C&D waste is mentioned below in Table 2.
Dry density Sample A Sample B Sample C Sample D Density range as per IS 2185 for Grade B
Average Dry density (kg/m3) 1123 1205 1112 1210 1100-1500

[0038] Present invention allows 100% usage of the C&D waste, without requiring conventionally used additives like fly ash and strengthening agents like sand. Even without utilization of the additives and strengthening agents, construction blocks developed using the construction mixture obtained through present invention are able to achieve required compressive strengths, as described above with reference to Fig. 2 and Table 1. Further, the coarse aggregate is able to replace conventionally used gravels and the fine aggregate is able to replace conventionally used sand (natural or artificial). The hollow blocks developed using The construction mixture made out of C&D waste developed through present invention has high strength, high thermal insulation, small volume shrinkage, and are environment friendly. Alternatively, the present invention may use the C&D waste along with additives in minor quantities, if desired, depending on an application.
[0039] Fig. 3 illustrates a flow chart of a method for processing C&D waste, in accordance with an embodiment of the present subject matter. The order in which the method for processing C&D waste is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to implement the method or alternate methods. Additionally, individual blocks may be deleted from the method without departing from the spirit and scope of the subject matter described herein. Furthermore, the method can be implemented using suitable units or machineries.
[0040] At block 302, C&D waste may be received from one or more construction or demolition sites. The C&D waste may include several types of materials, such as mud, wood, metal, plastic, earth, rock, rubble, steel, reinforcement, brick, mortar, plaster, tiles, and concrete.
[0041] At block 304, a filtered waste may be obtained by segregating an undesired material from the C&D waste. The undesired material may comprise one or more of earth, wood, metal, plastic, rock, rubble, steel, reinforcement, brick, mortar, plaster, tiles, and concrete, and the filtered residue may comprise brick, mortar, plaster, and concrete.
[0042] At block 306, the filtered residue may be grinded to obtain a crushed material. The crushed material may have a maximum particle size of up to12mm. When it is determined that a portion of the crushed material has a size greater than the maximum particle size, the portion of the crushed material may be segregated and transferred to the crushing machine for grinding until the maximum particle size of up to 12mm is obtained.
[0043] At block 308, the crushed material may be separated into a coarse aggregate and a fine aggregate. The coarse aggregate may have a particle size ranging from 4.75mm - 12mm and the fine aggregate may have a particle size ranging up to 4.75mm.
[0044] At block 310, different concentrations of the coarse aggregate and the fine aggregate may be mixed together to prepare a construction mixture. Further, a binding material may be added to prepare the construction mixture.
[0045] Although implementations for methods and systems for processing C&D waste have been described in language specific to structural features and/or methods, it is to be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as examples of implementations for processing C&D waste.
[0046] The terms “or” and “and/or” as used herein are to be interpreted as inclusive or meaning any one or any combination. Therefore, “A, B or C” or “A, B and/or C” mean “any of the following: A; B; C; A and B; A and C; B and C; A, B and C.” An exception to this definition will occur only when a combination of elements, functions, steps or acts are in some way inherently mutually exclusive.
[0047] The embodiments above are intended to be illustrative and not limiting. Although the present invention has been described with reference to particular embodiments, those skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and scope of the invention. Any incorporation by reference of documents above is limited such that no subject matter is incorporated that is contrary to the explicit disclosure herein. , C , Claims:We Claim:
1. A method for processing construction and demolition waste (100), comprising:
receiving the construction and demolition waste (100);
segregating an undesired material (104) from the construction and demolition waste (100) to obtain a filtered residue (106), wherein the filtered residue (106) comprises brick, mortar, plaster, and concrete;
grinding the filtered residue (106) to obtain a crushed material (114) having a maximum particle size of up to 12mm; and
preparing a construction mixture (130) by mixing the crushed material (114) with a binding material (134) in a predetermined ratio, thereby processing the construction and demolition waste (100).

2. The method as claimed in claim 1, wherein the predetermined ratio of the crushed material (114) used for preparing the construction mixture (130) is present in a range of 60% to 95% by weight.

3. The method as claimed in claim 1, further comprising creating construction blocks using the construction mixture (130).

4. The method as claimed in claim 1, wherein the binding material (134) is cement.

5. The method as claimed in claim 1, wherein the predetermined ratio of the binding material (134) used for preparing the construction mixture (130) is present in a range of 5% to 40% by weight.

6. The method as claimed in claim 1, wherein grinding of the filtered residue (106) is carried by a crushing machine (116).

7. The method as claimed in claim 1, further comprising:
segregating a portion of the crushed material (114) having a size greater than the maximum particle size; and
grinding the portion of the crushed material (114) to obtain the maximum particle size up to 12mm.

8. The method as claimed in claim 1, wherein the undesired material (104) segregated from the construction and demolition waste (100) comprises one or more of earth, wood, metal, plastic, rock, rubble, steel, reinforcement, brick, mortar, plaster, tiles, and concrete.

9. The method as claimed in claim 1, further comprising separating the crushed material (114) into a coarse aggregate (122) of particle size ranging from 4.75mm -12mm and a fine aggregate (124) of particle size ranging up to 4.75mm.

10. The method as claimed in claim 3, wherein the construction blocks are one of perforated blocks, solid blocks, hollow blocks, aerated autoclaved blocks, bricks, paver blocks, lintel blocks, stretcher blocks, corner blocks, pillar blocks, jamb blocks, partition blocks, frogged brick blocks, and bullnose blocks.

11. The method as claimed in claim 3, wherein the construction blocks are cured in a humid environment.

12. The method as claimed in claim 9, further comprising utilizing 20% - 40% coarse aggregate (122) and 60% - 80% fine aggregate (124) for preparation of the construction mixture (130).