DESC:4. DESCRIPTION

FIELD OF THE INVENTION

The present invention relates to the light weight composite concrete block for walling application like exterior walls, partition walls for residential, commercial and compound walls etc.

BACKGROUND OF THE INVENTION
Masonry walls, despite being widely used in construction, come with several limitations. They are:
• Labour-intensive and required skilled workers needs more construction time and not cost effective.
• Low strength to weight ratio
• Brittle in nature: prone to cracking and failure under structural loads.
• Not suitable for seismic prone areas due to low structural integrity and brittle in nature.
• High wastage during the manufacturing and handling
• Poor thermal and sound insulation demands more energy for thermal comfort
• Highly porous in nature leads to moisture absorption, which can cause dampness, efflorescence, and long-term degradation.
• Incompatibility between mortar and brick surfaces for plastering coat leads to delamination between plaster coat and brick surface and water infiltration reduces the durability of paint coat.
• Incompatibility between mortar and brick surfaces demands thick mortar joints which increases the risk of weak joints, and water infiltration, reduces durability and stability.
• High-density bricks necessitate heavy structural elements.
• Small and irregular brick sizes, which can impact construction efficiency and overall aesthetic appeal.
• No/Limited scope of customization of brick element as per the requirement of structural application.
• Lack of interlocking system.
• The use of red bricks is largely restricted due to environmental concerns to preserve and protect the topsoil layer for agricultural purposes.
These limitations highlight the need for improved wall construction methods that enhance efficiency, durability, and structural performance.
Table-1: Summary of the various walling systems advantages and their limitations are mentioned below
Type Advantages Limitations

Clay Bricks - Strong and durable
- better thermal insulation compared to CC bricks
- Fire resistant
-Heavier in weight compared to modern light weight bricks
-High wastage during manufacturing and handling,
-Labour-intensive construction due to smaller in size
- High water absorption
-Intensive manufacturing process
-Low strength to weight ratio
-Porous, leading to efflorescence and dampness.
-Demands water proof coat for the on site application
-Required thick mortar joints
- Incompatibility between mortar and brick surfaces for plastering coat increases the risk of delamination between plaster coat and brick surface
-Small in size leads to more joints
-Lack of uniformity affecting precision and aesthetics.
- The use of red bricks is largely restricted due to environmental concerns to preserve and protect the topsoil layer for agricultural purposes.
-No scope for interlocking system
-Demands heavy structural elements due to heavy weight of bricks.
- Limited availability in all the places
Concrete (CC) Blocks /Flyash bricks - High strength and durability
-Fire resistant
- scope for onsite production
- Eco friendly due to the use of Flyash.
-Heavier in weight compared to modern light weight bricks
-High wastage during manufacturing and handling,
-Labour-intensive construction due to smaller in size
- High water absorption
-Intensive manufacturing process
-Low strength to weight ratio
-Porous, leading to efflorescence and dampness.
-Demands water proof coat for the on site application
-Required thick mortar joints
- Incompatibility between mortar and brick surfaces for plastering coat increases the risk of delamination between plaster coat and brick surface
-Small in size leads to more joints
-Lack of uniformity affecting precision and aesthetics.
-Limited scope for interlocking system
-Demands heavy structural elements due to heavy weight of bricks.
- Brittle in nature
AAC/CLC Blocks (Autoclaved Aerated Concrete)/ (Cellular Lightweight Concrete) - Light in weight
- Good thermal and sound insulation
- Environmentally friendly
- Precise dimensions
- Higher initial capital investment for manufacturing unit
- Brittle in nature, needs to handle carefully
- Highly porous, susceptible to moisture absorption, requiring waterproofing.
- Low compressive strength
-Leads to more wastage during handling
- Required water proof coat for the on site application
-No scope for interlocking system
-Incompatibility between mortar and brick surfaces for plastering coat leads to delamination between plaster coat and brick surface and water infiltration reduces the durability of paint coat.
- Inconsistency in the density of the bricks.
Interlocking Bricks - No need for mortar joint
- Ease of installation.
- Good aesthetic appeal
- Requires precise manufacturing
- Not suitable for high-rise buildings
- Limited availability
- No scope for design flexibility
-Heavier in weight
- Specialized construction knowledge required - Due to interlocking system without mortar joints leads an air gaps between the blocks which further leads to pests, termite and moisture absorption.
This table 1 provides a quick comparison of the advantages and limitations of each type of walling elements, helping in choosing the most suitable one based on project requirements.
Water absorption and moisture retention during the rainy season are major challenges, as indicated in current walling systems. Due to the tendency to absorb water, this phenomenon will ultimately result in an adhesion problem between the skin(plastering) and the bricks/blocks.

Lightweight concrete walling systems provide superior thermal insulation capabilities, significantly decreasing the consumption of energy for heating and cooling. Their thermal conductivity varies from 0.25 to 0.46 W/m·K, reliant upon the materials employed, including polystyrene beads or vermiculite aggregates (El-Gamal & Saadi, 2022).

Lightweight walling systems accelerate construction processes owing to their easy handling and installation, resulting in reduced labour costs and shortened project durations. Their design facilitates effective usage in many conditions, especially in cold regions where conventional masonry may deteriorate due to cracking and inadequate strength (Long et al., 2020).

Lightweight bricks tend to have higher water absorption rates, which can lead to durability issues in wet conditions. For instance, the water absorption capacity of certain lightweight bricks can reach up to 17%(Karna et al., 2024). This characteristic can compromise their structural integrity over time.

Despite the various advantages of lightweight bricks, concerns remain regarding their long-term durability and performance in adverse conditions. Also, the compressive strength of the available lightweight brick ranges from 4-8 MPa which is not suitable for all types of the walling applications. Additional study is required to tackle these problems and enhance their application across various construction circumstances. Based on these limitations, the current invention introduces a new technology while taking existing technology into account.
Knowledge about the existing products is essential before developing a new product. The development of the new technological products can help in enhancing the viability and address the shortcomings of existing materials in the market
The present invention overcomes the limitations of existing technology by introducing a waterproof pre-mortar coated interlocking composite block. This is achieved through a two-stage process as shown in the FIG.1: first, developing the core block, followed by applying the waterproof pre-mortar coating on all the six sides of the core block. In the current invention the lightweight water-proof pre-mortar coated interlocking composite block are modern construction materials engineered to improve thermal and sound insulation and decrease the overall structural weight. These blocks comprise of lightweight concrete core surrounded by an pre mortar coat by providing an interlocking system which makes the workers for the ease of installation. The aim of developing these blocks is to enhance energy efficiency in structures while preserving structural integrity. In the present invention the composite block is prepared with water proof pre-coated mortar by using a special admixture i.e., Graphene Oxide (GO) based chemical admixture.
The idea of a "lightweight and insulated design" is crucial in civil engineering applications. The size and weight of these building components considerably influence transportation costs, manufacturing and installation costs, and the efficiency of workers. The utilization of industrial waste materials in the construction of precast elements not only leverages their lightweight and insulating capabilities but also boosts sustainability and promotes eco-friendly products. Choosing suitable sustainable materials is essential for optimizing the design and production of lightweight components. This method guarantees durability, speedy installation, and enhanced insulation compared to traditional methods, while maintaining adequate strength, and desirable mechanical characteristics.

BRIEF SUMMARY OF THE INVENTION

The following presents a simplified summary of the disclosure in order to provide a basic understanding to the reader. This summary is not an extensive overview of the disclosure and it does not identify key/critical elements of the invention or delineate the scope of the invention. Its sole purpose is to present some concepts disclosed herein in a simplified form as a prelude to the more detailed description that is presented later.

It is therefore an object of the present invention to provide lightweight water-proof pre-mortar coated interlocking composite block

The present invention discloses the application of the water proof pre-coated mortar over the Light Weight Concrete (LWC) core blocks in precast moulds. The bond between the light weight core and the water proof pre-coated mortar is extremely strong because of the adoption of same parenting cementitious material by first installing the LWC core followed by the water proof pre-coated mortar.
The present invention gives an additional advantage of customizing the block with varying densities and thickness of core and pre mortar coat by considering the high degree of compatibility between the pre-mortar coat and the light weight core block. Additionally, the inclusion of an interlocking system simplifies installation and ensures watertight joints. Furthermore, adding color pigment to the pre-plaster mortar offers a high potential for achieving a standardized colors.

According to one aspect of the invention, the present invention focuses on the development of a lightweight, water proof pre-coated mortar interlocking composite block designed for walling applications. These blocks are composed of approximately 70-80% lightweight insulation materials for a given overall volume of the block. To prepare the block, a lightweight concrete core with polystyrene beads was first prepared as illustrated in the below FIG.3. Followed by applying the premortar coat of 5 to 15 mm thick on all the six sides to the core block to enhance strength and durability, the mix design is being tabulated in the below Table 2. This innovative design significantly reduces the block's overall density while ensuring excellent strength. The resulting composite block, insulated with Expanded Polystyrene (EPS) concrete offers superior sound insulation along with being strong and lightweight. It serves as an eco-friendly (Industrial waste: Ground Granulated Blast Furnace Slag (GGBS)) and versatile non-structural element suitable for multiple applications. This invention highlights an efficient approach to creating sustainable, high-performance walling solutions.

BRIEF DESCRIPTION OF THE DRAWINGS

The objectives as described above as well as the uniqueness of the proposed technology along with its advantages are better appreciated by referring to the following illustrative and non-limiting detailed description of the present invention along with the following schematic diagrams, wherein:

FIG.1 illustrates preparation of core block and shifting that core block to the another mold according to one embodiment of the invention.

FIG. 2 illustrates the spacing between the core block along with the corner according to one embodiment of the invention.

FIG. 3 illustrates a sample of a prepared core slab according to one embodiment of the invention.

FIG.4 illustrates the dimensions of tongue and groove system for the composite block according to one embodiment of the invention.

FIG.5 illustrates a 3D view of the finished block with tongue and groove of the single element according to one embodiment of the invention.

FIG.6 illustrates an isometric view of the blocks installation according to one embodiment of the invention.

FIG.7 illustrates the isometric view of the blocks installation for the complete wall according to one embodiment of the invention.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present invention in any way.

DETAILED DESCRIPTION OF THE INVENTION

It is to be understood that the present disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The present disclosure is capable of other embodiments and of being practiced or of being carried out in various ways. In addition, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

The use of “including”, “comprising” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items. Further, the use of terms “first”, “second”, and “third”, and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another.

Past research indicates that the compressive strength of LWC diminishes with a reduction in density. Conventional concrete usually possesses a density between 2300 and 2500 kg/m³, while LWC normally exhibits a density of under 1500 kg/m³.

Prior to production, all raw materials underwent preliminary laboratory tests, including specific gravity tests for cement, GGBS, and M-sand. Mechanical characteristics of the material were evaluated by casting and testing cubes, with all results recorded in the specification sheet Table 2.

The combinations used for making water proof pre-coated mortar were chosen based on the iterative process to suit the requirements of target strength ranging from 40 to 60 MPa and the hardened specimen dry densities ranging from 2200 to 2400 kg/m3. Similarly, for light weight core block the combinations were chosen considering a target strength ranging from 3 Mpa to 5 MPa and hardened specimen dry densities ranging from 400 kg/m3 to 600 kg/m3. The average overall density of the block falls under the range of 800-1100 Kg/m3. The ranges of raw materials used for making composite block were given in the Table 2 given below.

According to one embodiment of the invention, the composite block of the present invention is 500-1000 mm in length, 150-250 mm in height, and 100-200 in width. The spacing between the core block and the pre mortar coat is clearly illustrated in the FIG.2. Core block made of EPS concrete has been prepared. The use of industrial waste like GGBS is being used in the preparation of core block and pre-mortar. Coarse aggregate is being replaced with expanded polystyrene beads during the preparation of core block. Each core block will be customized to suit the density of the overall block based on the application. Pre-mortar coat of thickness varying from 5-15 mm can be customized and the mortar is coated on all the six sides of the lightweight block by maintaining the water proofing protective coat. The interlocking provision in the current invention facilitates ease of installation as shown in FIG.6. FIG.4 displays the dimensions of tongue and groove system for the composite block. The isometric representation of the block installation is clearly depicted in the illustration of FIG.7. Any self-curing thin mortar containing cementitious material can be utilized for jointing the blocks, facilitating a more efficient installation process.

The conventional manufacturing process requires the placement of blocks followed by plastering, which is both time-consuming and labor-intensive. Additionally, the existing technology presents a higher likelihood of delamination between the blocks and the post-plastering. Furthermore, wall curing is essential in traditional systems. In contrast, the innovative composite block eliminates the need for curing, as it is pre-plastered in the factory and cured under controlled conditions with the ease of installation, as it was provided with the interlocking system. The advantages of the current invention are clearly described in the Table 3. Table 4 clearly describes the advantages the present invention over the available technology.

Table 2: Technical Specification Sheet
1 Title of the invention Lightweight water-proof pre-mortar coated interlocking composite block
2 Application of the invention Masonry walls, walling application for building envelope walls, compound walls, partition walls, high rise buildings, sound proof structures, and energy efficient housings
3 Type of the product Precast/prefab modular composite light weight block.
4 Dimensions of the product Length: 500-1000 mm (about 3.28 ft)
Width: 100-200 mm (about 0.82 ft)
Thickness: 150-250 mm (about 0.65 in)
Properties
5 Skin (pre-mortar coat)
Compressive strength (As per IS 516: Part 1: Sec 1: 2021) 40-60 MPa
6 Skin coat (pre-mortar coat) Split tensile strength (As per IS 516: Part 1: Sec 1: 2021) 5.5-6.5 MPa
6 Light weight core (CLC/AAC/EPS concrete)
Compressive strength (As per IS 516: Part 1: Sec 1: 2021) 3-5 MPa
7 Flexural strength of pre-mortar coat
(As per IS 516: Part 1: Sec 1: 2021) 8-10 MPa
8 Water permeability
(As per IS 3085:1965) 19- 23 mm
9 Water absorption
(As per ASTM C 1012-1585) 3-5 %
10 Compression test of the block IS-3495 (Part-1) 13-16 MPa
11 Thermal conductivity of core block 0.2-0.25 W/m·K.
13 Density of pre-mortar coat
Density of core
Combined density of pre-mortar coat and core :2200-2400 Kg/m3
:400-600 Kg/m3
:800-1100 Kg/m3
14 Proportions for lightweight concrete core block
Material Quantity (kg/m3)
Cement (OPC 53 Grade) :250 to 250
Ground Granulated Blast Slag :75 to 125
Thermocole beads (10 kg density) :6 to 8
Water to binder ratio :0.38 to 0.45
PCE admixture superplasticizer in percentage of binder :0.5-1.5
Air-Entraining admixture :0.2-1

15 Proportions for pre-mortar coat
Material Quantity (kg/m3)
Cement (OPC 53 Grade) :400 to 500
Ground Granulated Blast Slag :200 to 300
Manufacture Sand :1000 to 1200
Water to binder ratio :0.28 to 0.32
Nano based superplasticizer in percentage of binder :0.7 % to 0.9%

Table 3: Advantages of lightweight water-proof pre-mortar coated interlocking composite block
Description Current Invention
Good acoustic and thermal insulation The core made of EPS beads provides excellent acoustic and thermal insulation, while a pre-mortar coat on all six sides enhances durability and ease of installation.
Concrete composition Pre mortar coat made with graphene based or nano-engineered admixtures and the core block made with EPS beads.
Reusable and relocatable The interlocking system allows mortar-free installation, making the blocks reusable and relocatable.
water proof plaster coat These blocks don’t require onsite application of the water proof plaster coat which saves lot of manpower and time. This also addresses issue of delamination between brick surface and the onsite application of the plaster coat.
Surface finish Achieves smooth finish with the addition of specialised graphene oxide based admixture.
Delamination The bond between the core block and the pre-mortar coat is extremely strong because of the adoption of same parenting material by first installing the LWC core followed by the pre-mortar coat.
Casting methodology Can be done with precast which is time saving and space.
Customization Huge scope for customization as per structural requirement of the walls by varying the densities of the core and thickness of the water proof plaster coat based on the application.
Durable As the water proof pre-mortar coat is covered on all the six sides of the light weight block there is a no chance of water absorption hence it is a highly durable.
Water resistant • Water absorption is negligible, as all six surfaces of the lightweight core are coated with a water proof pre-coated mortar.
Leakage Very negligible chances of occurring leakages because of pre-mortar coated with high-strength mortar skin coat.
Strength to weight ratio High chances for achieving high strength to weight ratio due to the composite action.
Interlocking The block features an interlocking system, making installation significantly easier, time-efficient, and eliminates the need of the skilled labor.
Curing As this a precast element curing is not necessary after installation.
Energy efficient The EPS-filled lightweight core makes the composite block energy-efficient.
Customisation The core density, thickness, and pre-mortar coat can be customized to suit different applications.
Colour customisation Adding colour pigment to the pre-plaster mortar offers a high potential for achieving a standardized colours.

According to one embodiment of the invention, a method for preparing lightweight water-proof pre-mortar coated interlocking composite blocks is disclosed. The method includes placing of lightweight core blocks in an empty mold and applying pre- mortar skin water proof coat to the light weight core block on all the six sides of the light weight block. The casting of the composite blocks is done in two stage process. The core blocks are first cast in gang molds and transferring of said core blocks to second gang mold where the pre-mortar coat is applied to all the six sides of the core. Tongue-and-groove is adopted in the gang mold in which the interlocking structure is formed on the four sides of the composite blocks. Further, the core is selected from any lightweight block such as EPS (Expanded Polystyrene) concrete/ Autoclaved Aerated Concrete (AAC) /Cellular Lightweight Concrete (CLC)/ Foam Aerated Concrete (FAC) for reducing density while maintaining strength.

According to one embodiment of the invention, the block holds the possibility to produce customized light weight protective pre-mortar skin coat interlocking composite block by adjusting densities and thickness of core block and pre-mortar skin coat thickness.

According to one embodiment of the invention, the composite block comprises a specialized graphene oxide-based chemical admixture in the water-proof pre-mortar skin coating which gives high strength compared to the other walling elements, which fully envelops the lightweight core, thereby eliminating the need for on-site plastering and curing by providing enhanced water resistance with reduced water absorption and permeability.
Further, by adding the thin mortar for the amalgamation of blocks during installation to enhance ease of construction, alignment, leak proofing and high structural strength to the mason wall.
According to one embodiment of the invention, the tongue-and-groove interlocking structure on the composite blocks ensures structural alignment and eliminates the need for thick mortar joints during installation with unskilled manpower by saving the time of constructing the mason wall.
According to one embodiment of the invention, the composite block has a significantly good acoustic and thermal conductivity for enabling energy efficiency in constructions that employ the composite walling system. The bond between the core block and the pre-mortar skin coat is extremely strong because of the adoption of same parenting material.

Salient features of the present invention
The lightweight water-proof pre-mortar coated interlocking composite block serves as an effective alternative to cast in-situ brick, Foam Aerated Concrete (FAC) blocks, for building envelope walls, internal partition walls, and compound walls.

The present invention is a lightweight water-proof pre-mortar coated interlocking composite block with good insulation properties for walling applications.
Prefab/precast modular block
Light in weight
Fully composite action between pre-mortar coat and light weight core block (No delamination)
Easy installation due to the provision of interlocking system
Good acoustic and thermal insulation
Water resistant
Reusable and relocatable
On site application of water proof plaster coat is not required
High strength to weight ratio
Color customization
Leak proof joints
Strong fire rating
Highly durable
Termite resistant
Energy efficient
High scope for customization
Eco-friendly
Space saving

It will be recognized that the above described subject matter may be embodied in other specific forms without departing from the scope or essential characteristics of the disclosure. Thus, it is understood that, the subject matter is not to be limited by the foregoing illustrative details, but it is rather to be defined by the appended claims.

While specific embodiments of the invention have been shown and described in detail to illustrate the novel and inventive features of the invention, it is understood that the invention may be embodied otherwise without departing from such principles.

,CLAIMS:1. A method for preparing lightweight water-proof pre-mortar coated interlocking composite blocks, the method comprising:
i) placing of lightweight core blocks in an empty mold;
ii)applying pre- mortar skin water proof coat to the light weight core block on all the six sides of the light weight block;
characterized in that
casting of the composite blocks is done in two stage process;
the core blocks are first cast in gang molds and transferring of said core blocks to second gang mold where the pre-mortar coat is applied to all the six sides of the core;
tongue-and-groove is adopted in the gang mold in which the interlocking structure is formed on the four sides of the composite blocks.
2. The method as claimed in claim 1, wherein the core is selected from any lightweight block such as EPS (Expanded Polystyrene) concrete/ Autoclaved Aerated Concrete (AAC) /Cellular Lightweight Concrete (CLC)/ Foam Aerated Concrete (FAC) for reducing density while maintaining strength.
3. The method as claimed in claim 1, wherein the block holds the possibility to produce customized light weight protective pre-mortar skin coat interlocking composite block by adjusting densities and thickness of core block and pre-mortar skin coat thickness.

4. The method as claimed in claim 1, wherein the composite block comprises a specialized graphene oxide-based chemical admixture in the water-proof pre-mortar skin coating which gives high strength compared to the other walling elements, which fully envelops the lightweight core, thereby eliminating the need for on-site plastering and curing by providing enhanced water resistance with reduced water absorption and permeability.
5. The method as claimed in claim 1, wherein by adding the thin mortar for the amalgamation of blocks during installation to enhance ease of construction, alignment, leak proofing and high structural strength to the mason wall.
6. The method as claimed in claim 1, wherein tongue-and-groove interlocking structure on the composite blocks ensures structural alignment and eliminates the need for thick mortar joints during installation with unskilled manpower by saving the time of constructing the mason wall.
7. The method as claimed in claim 1, wherein the composite block has a significantly good acoustic and thermal conductivity for enabling energy efficiency in constructions that employ the composite walling system.

8. The method as claimed in claim 1, wherein the bond between the core block and the pre-mortar skin coat is extremely strong because of the adoption of same parenting material.