WO2015170960A1

WO2015170960A1 - Lightweight concrete composite from renewable resources

Info

Publication number: WO2015170960A1
Application number: PCT/MY2015/000028
Authority: WO
Inventors: Bin Mat Sohif; Aini Binti Mohd Sari Kamarul; Binti Haji Badri Khairiah; Fauzi Bin Mohd Zain Muhammad; Dato' Ar Dr Elias Bin Salleh Emeritus
Original assignee: UNIVERSITI KEBANGSAAN MALAYSIA
Current assignee: UNIVERSITI KEBANGSAAN MALAYSIA
Priority date: 2014-05-05
Filing date: 2015-05-05
Publication date: 2015-11-12
Anticipated expiration: 2016-11-05
Also published as: MY172688A

Abstract

The invention relates to a process of producing lightweight construction and building materials such as lightweight concrete using natural oil-based polyurethanes as fillers in the composition. The lightweight concrete is produced by introducing natural oil-based polyurethane as the green lightweight aggregate. The natural oil-based polyurethane consists of natural oil polyester polyol and polyisocyanates formed through polymerization process. The polyurethane aggregates perform as fillers and insulation materials. The novel lightweight concrete is light in weight, excellent compression strength for structural and non- structural elements and good thermal insulation effects. The natural-based lightweight concrete possessed good compressive strength and also allowed better workability and thermal efficiently as structural functions especially for building construction.

Description

TITLE: LIGHTWEIGHT CONCRETE COMPOSITE FROM RENEWABLE RESOURCES

TECHNICAL FIELD:

The present invention relates to the field of construction and building materials. The term building and construction material is then referred to as concrete thereafter.

Particularly, this invention relates to the field of composite building material structures.

More particularly, the invention relates to the field of lightweight building material composite.

Even more particularly, the invention provides a lightweight building material composite from renewable natural resources.

Even more particularly the present invention relates to a process for the production of lightweight building material composite using natural resources.

BACKGROUND AND PRIOR ART:

The lightweight building material can be produced by introducing lightweight aggregate, such as expanded clay, expanded polystyrene, polyurethane etc.

Common concrete produced is in the density range of 2400 kg/m³. The last decade has seen great strides in the realm of dense concrete and fantastic compressive strengths (up to 20,000 psi) which mix designers have achieved. Yet regular concrete has some drawbacks. It is heavy, hard to work with, and after it sets, one cannot cut or nail into it without some difficulty or use of special tools. Several approaches have been introduced by using agricultural wastes as fillers in order to get rid of the heavy weight of the normal concrete composite but this caused some other effects such as damp concrete and high water-sorption due to the hydrophilicity of the agricultural biomass. Lightweight concrete can be produced by introducing lightweight aggregates, such as expanded clay, expanded polystyrene, polyurethane, and so on. Within the wide range of plastics materials, the manufacture of polyurethane (PU) by reacting polyisocyanate with the polyol offers broad spectrum of applications. The properties of polyurethane products can be controlled chemically and physically in such a manner that different properties are achieved. In general, most polyols used in the polyurethane industry are petroleum-based, where crude oil and coal are used as starting raw materials. However, the prices of these polyols are high because of the high technology processing system to not only manufacturing the polyols but also the polyisocyanates.

Lightweight concrete has a density less than 1800 kg/m³. It is common to use aggregates such as expanded shale, clay, vermiculite, pumice, cement, fibre, wood and scoria among others. Decreasing the weight and density produces significant changes which improves many properties of concrete, both in placement and application. Although this has been accomplished primarily through the use of lightweight aggregates, since 1928 various preformed foams have been added to the concrete mixture, further reducing the weight. The very lightest concrete mixtures (320 to 960 kg/m³) are often made using foam as the aggregate, and are referred to as cellular concrete. The entrapped air takes the form of small, macroscopic, spherically shaped bubbles uniformly dispersed in the concrete mix. Today foams are available which have a high degree of compatibility with many of the admixtures currently used in modern concrete mix designs. Normal concrete structures contains much weight in comparison and are also not cost effective, in areas where earthquake are common the normal concrete structure may cause much harm, whereas if the structure comprises of lightweight composite structure then in that case the danger can be minimized. Therefore it is very important to provide solutions which can solve the above problems in innovative manner. The present invention aims to provide much better solution for the above mentioned problems, and provide a lightweight concrete composite from renewable natural resources.

Reference may be made to United States Patent 8,590,239, titled "Construction made of individual components" by Bathon, T., dated 13.01.2006. This invention relates to a construction made of individual components which consist at least partially of wood-concrete composite elements (100) composed by at least one wood component (1 10) with a wood cross section and a concrete component (101 ) with a concrete cross section. The wood-concrefe composite elements are at least partially prefabricated and then brought together at the factory or later at the construction site. The individual components are connected and/or assembled with the other components by a non-positive and/or positive and/or material connection, partially by transmitting force only via the wood cross section or partially only by transmitting force via the concrete cross section or partially by the wood cross section and the concrete cross section.

Reference may be made to United States Patent 8,245,470 titled "Wood -concrete- composite systems" by Bathon T. and Bathon L, dated 21.08.2012. This invention relates to a wood concrete composite system has a wood construction component, an intermediate layer and a concrete construction unit. The concrete construction unit has at least one side which faces the wood construction component. Thus at least single intermediate layer creates at least a partial separation between the wood and concrete. Reference may be made to United States Patent 7,820,094 titled "Lightweight concrete compositions" by Guevara T. et al., dated 18.12.2009. This invention relates to a lightweight ready-mix concrete composition that contains 8-20 volume percent cement, 1 1-50 volume percent sand, 10-31 volume percent prepuff particles, 9-40 volume percent coarse aggregate, and 10-22 volume percent water, where the sum of components used does not exceed 100 volume percent;. The prepuff particles have an average particle diameter of from 0.2 mm to 8 mm, a bulk density of from 0.02 g/cc to 0.64 g/cc, an aspect ratio of from 1 to 3. The slump value of the composition measured according to ASTM C 143 is from 2 to 8 inches. After the lightweight ready-mix concrete composition is set for 28 days, it has a compressive strength of at least 1400 psi as tested according to ASTM C39.

Reference may be made to United States Patent 8,029,617 titled "Lightweight concrete compositions" by Guevara T. et al., dated 04.11.2009. This invention relates to a lightweight concrete composition containing from 10 to 90 volume percent of a cement composition, from 10 to 90 volume percent of particles having an average particle diameter of from 0.2 mm to 8 mm, a bulk density of from 0.03 g/cc to 0.64 g/cc, an aspect ratio of from 1 to 3, and from 0 to 50 volume percent of aggregate; where the sum of components used does not exceed 100 volume percent, and where after the lightweight concrete composition is set it has a compressive strength of at least 1700 psi as tested according to ASTM C39 after seven days. The concrete composition can be used to make concrete masonry units, construction panels, road beds and other articles.

Reference may be made to United States Patent 7,681 ,368 titled "Concrete composite wall panel" by Rubio E., dated 23.03.2010. This invention relates to A composite wall panel for exterior walls of a structure includes a polymeric foam core having a C-stud framing system embedded therein and an exterior and/or interior facing formed of a reinforced concrete bonded to the core surface and mechanically attached to the studs thereby providing increased strength, insulation and resistance to environmental conditions.

Reference may be made to United States Patent 7,632,348 titled "Lightweight concrete compositions containing antimicrobial agents" by Cowan D.A. et al., dated 15.12.2009. This invention relates to a lightweight concrete composition containing from 10 to 90 volume percent of a cement composition, from 10 to 90 volume percent of particles having an average particle diameter of from 0.2 mm to 8 mm, a bulk density of from 0.03 g/cc to 0.64 g/cc, an aspect ratio of from 1 to 3, and from 0 to 50 volume percent of aggregate, where the particles contain an antimicrobial agent; where the sum of components used does not exceed 100 volume percent, and where after the lightweight concrete composition is set it has a compressive strength of at least 1700 psi as tested according to ASTM C39 after seven days. The concrete composition can be used to make concrete masonry units, construction panels, dining tables, counter surfaces, bench tops, and/or examination tables as well as other articles.

Reference may be made to United States Patent 7,276,551 titled "Cement composition" by Pageau JR., dated 02.10.2007. This invention relates to a novel cement composition. This cement may be combined with a number of different products, including residual materials such as polystyrene, glass, cork, fiberglass, cellulose fibers, wood fibers and wood shavings, as well as with minerals or compositions such as zonolite or vermiculite. The resultant concrete exhibits physical and chemical characteristics that make it suitable for use in construction projects, including resistance to freeze-thaw cycles.

Reference may be made to United States Patent 6,827,570 titled "Method and apparatus for manufacture of unitary lightweight concrete composite blocks" by Sumrall O.F. et al., dated 07.12.2004. This invention relates to a process and apparatus for manufacturing unitary concrete blocks includes a form that defines the desired shape of the unitary concrete block. A form loading station delivers a lightweight concrete composite into the form. A station conveyor conveys the form from the form loading station through a curing oven. In the curing oven, the composite-filled form is cured into a unitary concrete block. The station conveyor conveys the form to a block removal station that removes the unitary concrete block from the form. The station conveyor returns the form to the form loading station to manufacture more unitary concrete blocks. For increased production, multiple forms can be conveyed between stations simultaneously. Additionally, a metering ingredient assembly may be used to deliver appropriate amounts of desired ingredients to a mixer for producing the lightweight concrete composite. Reference may be made to United States Patent 6,746,532 titled "Lightweight concrete with increased strength and process for producing the same" by Boronkay G., dated 08.06.2004. This invention relates to a process for producing lightweight concrete is disclosed which comprises mixing foamed particles, aggregates, and cement slurry to create a strong, lightweight concrete. The foamed particles can be created by grinding foamed plastic waste material. The aggregates comprise soluble glass, water, and polyvinyl acetate. One embodiment includes batching the cement in two stages. The concrete is pressed to within 65- 70% of its volume prior to drying. Lightweight concrete comprising foamed plastic particles mixed with cement, water, soluble glass, and polyvinyl acetate is also disclosed, where the concrete, after compacting and drying possesses greater strength than common polystyrofoam concrete. Reference may be made to United States Patent 8,167,996 titled "Lightweight structural concrete provided with various wood properties" by Bui T., dated 01.05.2012. This invention relates to A lightweight structural concrete with screw- ability and nail-ability similar to wood is composed of a non-structural and ultra- lightweight aggregate such as expanded perlite or a combination of expanded perlite and polystyrene beads of a particular size distribution and volume amount, entrained air cells of another specific size distribution and volume amount, and dense cementitious composition of a cement binder, a fine grade structural filler no larger than concrete sand grade, a pozzolan, and optional micro-fibers for reinforcement. This structural concrete matrix is optimized to hold 13 gauge T-nails and bugle head wood screws with thread ranging from 8 to 11 threads per inch and diameter of 0.10" to 0.137". The resulting concrete will have consistent screw- ability and nail-ability similar to that of wood.

However none of the inventions in prior art comprise of a building material composite as the present invention does. The present invention comprises of building material composite filled with natural oil-based polyurethanes as lightweight aggregates in the form of fine particles based on selected natural resources consisting of palm oil, palm kernel oil and/or coconut oil converted to polyester. These polyesters are then used as basic reactants to form polyurethane. The present invention is a unique process of mixing and production of lightweight aggregates and lightweight concrete. The present invention uses natural oil-based polyurethane as lightweight aggregate and comprises green lightweight aggregate. Rigid polyurethane with 0.5 to 10 mm particle size is applied as fillers to reduce the weight and increase thermal conductivity of the concrete composite.

DISCLOSURE OF THE INVENTION Objects of the invention:

The primary objective of the invention is to produce lightweight building material/ concrete composites.

Another main objective of the invention is to provide a process on the mixing and production of lightweight aggregate and lightweight concrete.

Another objective of the invention is to provide/utilize natural oil-based polyurethane as lightweight aggregate.

Another objective of the invention is to provide a lightweight concrete filled with green lightweight aggregate.

Another objective of the invention is to produce lightweight aggregates from natural resources such as, palm oil (PO), and palm kernel oil (PKO) and/or coconut oil.

Another objective of the invention is to produce a range of lightweight concrete composites based on density and compressive strength.

A further objective of the invention is to produce lightweight concrete composite with high mechanical strength and excellent thermal conductivity. Summary of the invention:

This invention provides a complete solution for problems relating to the regular concrete composite in terms weight, strength and insulation properties. The present invention comprises of building material/ concrete composite filled with natural oil-based polyurethanes as lightweight aggregates in the form of fine particles based on selected natural resources consisting of palm oil, palm kernel oil and/or coconut oil converted to polyesters. These polyesters are then used as basic reactants to form polyurethane. Rigid polyurethane with 0.5 to 10 mm particle size is applied as fillers to reduce the weight and enhance thermal insulation property.

Disclosure of the Invention:

Embodiments of the present invention aim to provide a novel and unique lightweight concrete composite using natural resources. The present invention provides a process for producing lightweight aggregate or fine particles based on natural resources such as palm oil, palm kernel oil (PKO) and/or coconut oil modified into polyurethane combine into mortar consists of cement binder, sand, admixtures and water. Rigid polyurethanes with particle size ranging from 0.5 to 10 mm are applied as fillers to reduce the weight of the concrete composite. The density of the present lightweight concrete composite is less than 1800 kg/m³ and classify as lightweight concrete. This lightweight concrete composite have excellent thermal conductivity, compressive strength, easy to manufacture and/or assemble. The lightweight concrete composite under the present invention has the widespread use item in construction and insulation purpose application especially building materials, high or low rise building, marine structure, bridge and the like.

This invention presents the usage of a natural material, such as palm oil, palm kernel oil and coconut oil converted to polyester polyol as alternative to petroleum- based polyesters in the polyurethane (PU) industry. Usage of PL) polyol in the concrete mixture has not been reported elsewhere. The PU systems consist of polyester polyol from the natural oil such as palm kernel oil and 2, 4-methylene diphenyldiisocyanate (crude MDI). The molecular weight and the functionality of polyols affect the resulting foam properties. Polyisocyanates act as the curing agent. Therefore, urethane and related foams are recognized as building block polymers. The case of palm kernel oil produced palm-based PU system and is used in the case study. The palm-based lightweight concrete in this invention exclusively considers structural and non-structural lightweight concrete, that is a mixture of ordinary cement, fine sand, admixtures (plasticizing agent), water, and PU particles, as fine aggregates ranging from 0.5 to 10 mm. Normal weight concrete mixture typically have densities above 2400 kg/m³, whereas lightweight concrete (LWC) has a density ranging from 800 kg/m³ to 1800 kg/m³. Structural lightweight concrete has minimum of 17 Pa at 28-days compression strength comparable to normal weight concrete. The present invention provides methods of preparation of the rigid polyurethane (PU) with density above 200 kg/m³, the lightweight aggregate namely palm-based PU, the mortar system and the lightweight concrete mixture. The properties of these systems are described.

In accordance with the embodiments of the present invention, there is provided the usage of natural oil-based PU, in this case palm-based PU (pPU). Polyurethane under the present invention is used for wide applications such as rigid foam, elastomer, coating, adhesive and sealant. The usage of pPU in the making of concrete make the present lightweight aggregate concrete composite much more novel and unique with less weight, excellent thermal insulation property and high strength in comparison with the regular concrete composite and other prior arts. The PU system of the present invention comprises of natural oil polyol and 2, 4- methylene diphenyldiisocyanate (crude MDI) and can also be any other isocyanate derivatives. The molecular weight and the functionality of polyols affect the resulting foam properties. Polyisocyanates act as the hardener or curing agent. Therefore, urethane and related foams are used as building block polymers in the present invention. In accordance with the embodiments of the present invention, natural oil-based polyeater polyol which thereafter known as palm kernel oil-based polyol or PKO-p and MDI were mixed using an overhead stirrer at a speed of 800 to 2000 rpm for less than 5 min depending on the mass and composition of the polyurethane system. The mixture was then poured into a mold, and was allowed to cure for 5 to 20 min. Rigid PU foam was demolded and conditioned at room temperature for 16 to 24 hr prior to characterizations. The ratio of PKO-p to MDI was varied from 1 to 3 such as 1 :1 to 1 :3 or 3:1 ratio of PU system. This PU system functioned as the lightweight aggregate in concrete, upon curing was ground and sieved to a size of 0.5 to 10 mm prior to usage in the mortar system.

In accordance with the embodiments of the present invention, the formulation of palm-based lightweight concrete is identified less than 1800 kg/m³. The loading percentage of the PU and water per cement ratio are the most effective and dominant parameters that affect the density and compressive strength, therefore the loading percentage of PU system and w/c ratio are set as varying variables.

In accordance with the embodiments of the present invention, the 0.2 to 0.8 w/c (water per cement) ratio with 1 to 20% (w/w) PU system were optimized ratio and processed composition, the palm-based lightweight concrete composition of the present invention was prepared by integrating cement, sand and w/c at a ratio of 0.1 :0.2:0.2 to 1 :5:0.8 in a drum mixer. About 1 to 20% (w/w) of PU system with size of 0.5 to 10 mm were mixed into the concrete mixture until uniformly distributed, the polyurethane aggregate were mix through dry and pre-wetted process and then the mixture casted in steel molds of 100 mm x 100 mm x 100 mm dimensions and demold after 24 hr for further characterization.

In accordance with the embodiments of the present invention, the density of PU rigid foam (kg/m³) was determined following BS4370: Part 1 : 1988 (Method of test for rigid cellular materials: Determination of apparent density). In accordance with the embodiments of the present invention, the density of the lightweight concrete is calculated using BS EN 12390: Part 7: 2002 standard (Testing hardened concrete: Density of hardened concrete). In accordance with the embodiments of the present invention, a compressive strength test was conducted according to BS EN 12390: Part 3: 2001 standard (Testing hardened concrete: Compressive strength of test specimens). They are tested based on exposure time of 7, 14 and 28 days. The compressive stress and load peak data were recorded.

The present invention indicates the effects of pPU on the density of the lightweight concrete with various water/cement (w/c) ratios of the concrete mix. The w/c ratios varied 0.2-0.8 with 0.2-15% (w/w) PU loading. The density was obtained approximately in the range of 800-1900 kg/m³.

In accordance with the embodiments of the present invention, the compressive strength of the pPU was in the range of 3.0 MPa to 15.0 MPa.

The present invention indicates that at 28 days of the industrial testing standard, the compressive strength of the lightweight concrete ranges from 12.0 MPa to 25.0 MPa.

In accordance with the embodiments of the present invention, there is provided a lightweight concrete and a technology for the production thereof, said technology utilizing a light weight aggregate, a mortar comprising of ordinary cement, fine sand, admixtures and water with a density ranging from 800-1900 kg/m³ such that the resulting lightweight concrete has high mechanical strength and excellent thermal conductivity, lightweight aggregate comprising of polyurethane with hard and soft segments formed from the reaction between polyisocyanates and natural oil-based polyester polyols so that the resulting concrete is having excellent propertiesalong with being environment friendly, recyclable and renewable due to some of the main ingredients being natural in nature. In an embodiment, said light weight aggregate is preferably palm-based polyurethane. In another embodiment, said concrete mix comprises of ordinary cement, fine sand, admixtures and water to make the composition.

In another embodiment, said composition is mixed in the ratio of 0.2 to 0.8 w/c (water to cement) ratio depending upon the requirement.

In another embodiment, said composition optionally may contain admixtures such as super plasticizers, silica fume, rice husk ash, residual ash, quarry dust and fly ash as per the requirement. In another embodiment, said composition may contain fine sand which is river sand with size less than 5 mm as per the requirement.

In another embodiment, the palm-based lightweight concrete composition of the present invention is prepared by integrating cement, sand, admixtures and w/c at a ratio in the range of 0.1 :0.2:0.1 :0.2 to 1 :5:1.0:0.8 in a drum mixer.

In another embodiment, said polyisocyanates are preferably 2,4-methylene diphenyldiisocyanate or 4,4-methylene diphenyldiisocyanate or also other isocyanate derivatives. In another embodiment, said natural oil-based polyester polyol may consist the selected natural oil namely palm oil, palm kernel oil and/or coconut oil.

In another embodiment, the ratio of natural oil-based polyester polyol to polyisocyanates vary from 1 to 3 such as 1 :1 to 1 :3 or 3:1 ratio In another embodiment, said lightweight aggregates are preferably rigid polyurethane with a particle si?e in the range of 0.5-10 mm.

In another embodiment, said lightweight aggregates are preferably rigid polyurethane with density in the range of 42-450 kg/m³.

In another embodiment, said lightweight aggregates are preferably rigid polyurethanewith compressive strength in the range of 3.0-15 MPa. In another embodiment, said lightweight aggregates are preferably rigid polyurethane with thermal conductivity less than 0.055 W/rn-K.

In another embodiment, said lightweight aggregates may also be possibly polyurethane wastes from industry which could possibly be out of specification, out of life or trimmed wastes.

In another embodiment, rigid polyurethane is added to the concrete at the ratio of 0.2 to 15% (w/w) depending upon the requirement. In another embodiment, there is provided the technology for the production of lightweight concrete, for producing novel lightweight building and construction materials ie lightweight concrete utilizing the blending method using the composition of present invention i.e. ordinary cement, fine sand, admixtures water and natural oil-based polyurethane particles as fine aggregates, polyisocyanates (and natural oil-based polyols; said process comprising of two stages.

In another embodiment, said first stage involves the preparation of the polyurethane by mixing using an overhead stirrer at a speed of 800 to 2000 rpm for less than 5 min depending on the weight and proportions through polymerization reaction; then pour the said mixture into a mold, and allowing the same to cure for 5 to 20 min so as to obtain a rigid polyurethane foam; then demold and condition said rigid foam at room temperature for 10 to 25 hours in order to obtain the desired characteristics of the end product.

In another embodiment, said second stage involves drum-mixing of the mortar system with polyurethane aggregates for less than 10 min, pour into the mold and demold after 24 hr. The curing process maybe dry-cure and wet-cure until 28 days and undergoes characterization.

In another embodiment, said step of drum-mixing is preferably conducted by four approaches:

• Forming the mortar system into wet blend and adding the polyurethane aggregate into the system and further mixing to form well-mixed mixture, or

• Pre-wetting the polyurethane aggregate prior to mixing in the dry mortar system and further mixing to form well-mixed mixture, or

· Adding the dry mortar to the pre-wetted polyurethane aggregate and further mixing to form well-mixed mixture, or

• Mixing the polyurethane aggregate with the dry mortar to form dry mixture and adding water to form the wet concrete mix and furthering mix to form well-mixed mixture.

In another embodiment, the lightweight concrete and other related materials are used as few of the main ingredients and act as building insulation, blocks, bricks, walls, wall partitions, roof, floor and others building envelope for the lightweight concrete composite.

Claims

Claims:

1. A lightweight concrete and a technology for the production thereof, said technology utilizing a light weight aggregate, a mortar comprising of ordinary cement, fine sand, admixtures and water with a density ranging from 800-1900 kg/m³ such that the resulting lightweight concrete has high mechanical strength and excellent thermal conductivity, lightweight aggregate comprising of polyurethane with hard and soft segments formed from the reaction between polyisocyanates and natural oil-based polyester polyols so that the resulting concrete is having excellent properties along with being environment friendly, recyclable and renewable due to some of the main ingredients being natural in nature.

2. The lightweight concrete and a technology for the production thereofas claimed in Claim 1 , wherein said light weight aggregate is preferably palm- based polyurethane.

3. The lightweight concrete and a technology for the production thereof as claimed in Claim 1 , wherein said concrete mix comprises of ordinary cement, fine sand, admixtures and water to make the composition.

4. The lightweight concrete and a technology for the production thereof as claimed in Claim 3, wherein said composition is mixed in the ratio of 0.2 to 0.8 w/c (water to cement) ratio depending upon the requirement.

5. The lightweight concrete and a technology for the production thereof as claimed in Claim 3, wherein said composition optionally may contain admixtures such as super plasticizers, silica fume, rice husk ash, residual ash, quarry dust and fly ash as per the requirement.

6. The lightweight concrete and a technology for the production thereof as claimed in Claim 3, wherein said composition may contain fine sand which is river sand with size less than 5 mm as per the requirement.

7. The lightweight concrete and a technology for the production thereof as claimed in Claim 3, wherein the palm-based lightweight concrete composition of the present invention is prepared by integrating cement, sand, admixtures and w/c at a ratio in the range of 0.1 :0.2:0.1 :0.2 to 1 :5:1.0:0.8 in a drum mixer.

8. The lightweight concrete and a technology for the production thereof as claimed in Claim 3, wherein said lightweight concrete are preferably has high mechanical strength with compressive strength in the range of 1.0-24.0 MPa.

9. The lightweight concrete and a technology for the production thereof as claimed in Claim 3, wherein said lightweight concrete are preferably has excellent insulation properties with thermal conductivity less than 0.40 W/m-K.

10. The lightweight concrete and a technology for the production thereof as claimed in Claim 1 , wherein said polyisocyanates are preferably 2,4- methylene diphenyldiisocyanate or 4,4-methylene diphenyldiisocyanate or also other isocyanate derivatives.

11. The lightweight concrete and a technology for the production thereof as claimed in Claim 1 , wherein said natural oil-based polyester polyol may consist the selected natural oil namely palm oil, palm kernel oil and/or coconut oil.

12. The lightweight concrete and a technology for the production thereof as claimed in Claim 1 , wherein the ratio of natural oil-based polyester polyol to polyisocyanates vary from 1 to 3 such as 1 :1 to 1 :3 or 3:1 ratio

13. The lightweight concrete and a technology for the production thereof as claimed in Claim 1 , wherein said lightweight aggregates are preferably rigid polyurethane with a particle size in the range of 0.5-10 mm.

14. The lightweight concrete and a technology for the production thereof as claimed in Claim 1 , wherein said lightweight aggregates are preferably rigid polyurethane with density in the range of 42-450 kg/m³.

15. The lightweight concrete and a technology for the production thereof as claimed in Claim 1 , wherein said lightweight aggregates are preferably rigid polyurethane with compressive strength in the range of 3.0-15 MPa.

16. The lightweight concrete and a technology for the production thereof as claimed in Claim 1 , wherein said lightweight aggregates are preferably rigid polyurethane with thermal conductivity less than 0.055 W/m-K.

17. The lightweight concrete and a technology for the production thereof as claimed in Claim 1 , wherein said lightweight aggregates may also be possibly polyurethane wastes from industry which could possibly be out of specification, out of life or trimmed wastes.

18. The lightweight concrete and a technology for the production thereof as claimed in Claim 1 , wherein rigid polyurethane is added to the concrete at the ratio of 0.2 to 15% (w/w) depending upon the requirement.

19. The technology for the production of lightweight concrete as claimed in Claim 1 , for producing novel lightweight building and construction materials ie lightweight concrete utilizing the blending method using the composition as in Claim 2 i.e. ordinary cement, fine sand, admixtures water and natural oil-based polyurethane particles as fine aggregates, polyisocyanates (and natural oil-based polyols; said process comprising of two stages.

20. The technology for the production of lightweight concrete as claimed in Claim 17, wherein said first stage involves the preparation of the polyurethane by mixing using an overhead stirrer at a speed of 800 to 2000 rpm for less than 5 min depending on the weight and proportions through polymerization reaction; then pour the said mixture into a mold, and allowing the same to cure for 5 to 20 min so as to obtain a rigid polyurethane foam; then demold and condition said rigid foam at room temperature for 10 to 25 hours in order to obtain the desired characteristics of the end product.

21. The technology for the production of lightweight concrete as claimed in Claim 17, wherein said second stage involves drum-mixing of the mortar system with polyurethane aggregates for less than 10 min, pour into the mold and demold after 24 hr. The curing process maybe dry-cure and wet- cure until 28 days and undergoes characterization.

22. The technology for the production of lightweight concrete as claimed in Claim 17, wherein said step of drum-mixing is preferably conducted by four approaches:

a) Forming the mortar system into wet blend and adding the polyurethane aggregate into the system and further mixing to form well-mixed mixture, or b) Prewetting the polyurethane aggregate prior to mixing in the dry mortar system and further mixing to form well-mixed mixture, or

c) Adding the dry mortar to the pre-wetted polyurethane aggregate and further mixing to form well-mixed mixture, or

d) Mixing the polyurethane aggregate with the dry mortar to form dry mixture and adding water to form the wet concrete mix and furthering mix to form well-mixed mixture.

23. The technology for the production of lightweight concrete as claimed in Claim 17, wherein the lightweight concrete and other related materials are used as few of the main ingredients and act as building insulation, blocks, bricks, walls, wall partitions, roof, floor and others building envelope for the lightweight concrete composite.

24. An improved concrete composition from natural resources and a technology for the production thereof, as claimed in any of the proceeding claims.