COMPOSITE CONCRETE COMPOSITION AND METHOD OF PREPARATION THEREOF

Abstract

ABSTRACT COMPOSITE CONCRETE COMPOSITION AND METHOD OF PREPARATION THEREOF The present invention discusses a composite concrete composition primarily comprising an admixture of chemical admixture, powder content further including cement, SF and MK of 455, 53.5 and 26.75, FA of 589, CA of 1219 along with OPC, fiber percentage including ramie fibers and steel fibers varying between 0.5 to 2 % by weight where the total volume of the fibers is coming to 1 to 4 % of the total volume wherein the w/c ratio is 0.26. The resultant composite concrete mixture has improved tensile strength, compressive strength, flexural strength and modulus of elasticity with the advantages of low water absorption. The method of preparation includes mixing the ingredients at appropriate ratio, followed by casting and curing. Fig 8

Specification

Description:FIELD OF INVENTION
The present invention relates to concrete technology. The present invention specifically relates to composite concrete composition and its method of preparation, wherein the concrete composition works on incorporating a blend of natural and metal fibers providing a greener option.

BACKGROUND OF THE INVENTION
Insufficient materials availability leads the researchers to find alternate materials. This research mainly focuses on ramie fibers and hooked-end steel fibers-based composites, which have wide applications in the construction field. In this ramie fibers and hooked-end steel fibers are used in a hybrid form which exhibits synergistic responses from each fiber. There are different types of steel fibers available in markets, in that hooked-end fibers show enhanced performance. Generally composite material is used for high strength, stiffness and durability. By the usage of natural fibers (Ramie fibers), we can able to produce a green product which conserves energy and environment and can able to produce eco-friendly environment.

Though the prior arts discuss several concrete based compositions like the prior art AU2017396649 AA titled as CONCRETE AND METHOD FOR MANUFACTURING CONCRETE COMPOSITION discusses a concrete composition that has outstanding cost-effectiveness and environmental burden reduction, ensures material separation resistance and/or impact deformation resistance at a high level, and has outstanding workability. The present invention is a concrete composition comprising cement and ground fly ash formed by grinding fly ash raw powder, the ground fly ash being configured such that a fly ash paste that contains 50 parts by mass of water relative to 100 parts by mass of the ground fly ash has a JA funnel flow down time in the range of 17-27 seconds.

Another patent application US2024116815 A2 titled as LOW CARBON CONCRETE COMPOSITION AND A METHOD TO PRODUCE A LOW CARBON CONCRETE COMPOSITION discusses a concrete composition includes a hydraulic binder, wherein the hydraulic binder includes Portland clinker and mineral addition including limestone, or fly ash or combination thereof, the limestone and/or fly ash representing at least 50 percent by weight of the total weight of the binder; a cationic polymer having a cationic charge density greater than 0.5 meq/g, and an intrinsic viscosity less than 1 dl/g; a water-reducing additive comprising at least one phosphonic amino-alkylene group; aggregates, and water.

Yet another prior art US4172061 A titled as ASPHALTIC CONCRETE COMPOSITIONS COMPRISING HYDROGENATED DIENE/VINYL AROMATIC COPOLYMERS discusses a PG,1 Improved asphalt-containing compositions having excellent flexural fatigue test characteristics are prepared by incorporating into the mix during its preparation at least one hydrogenated diene/vinyl aromatic copolymer.

Though several prior arts focus on various compositions of concrete mixture none of them specifically focus on providing an composite concrete composition with a natural component wherein the invention focusses on the flexural strength of the hybrid fiber reinforced concrete which includes ramie fibers and hooked end steel fibers and works on reduction of waste production and energy during the artificial fiber production process providing a greener option of concrete composition. None of the prior arts discuss the synergistic composition where the flexural strength is reinforced.

OBJECTS OF THE INVENTION
The primary objective of the present invention is to provide a composite concrete mix composition comprising ramie fiber, hooked end steel fibers along with OPC and aggregates in a specific ratio.

It is another objective of the present invention to provide a method of preparation of composite concrete mix including ramie fiber, hooked end steel fibers along with OPC and aggregates in a specific ratio.

It is also another objective of the present invention to provide a reinforced concrete mix with additional mechanical and durable properties.
It is yet another objective of the present invention to provide a greener option of concrete mix incorporating natural fibers.


SUMMARY OF THE INVENTION
The following summary is provided to facilitate a clear understanding of the new features in the disclosed embodiment and it is not intended to be a full, detailed description. A detailed description of all the aspects of the disclosed invention can be understood by reviewing the full specification, the drawing and the claims and the abstract, as a whole.

This invention focusses on the flexural strength of hybrid fiber reinforced concrete (Ramie fibers and Hooked-end steel fibers). Natural fiber utilization in concrete is an innovative technique, by this we can able to reduce the waste production and energy during the artificial fiber production process. In general, hybrid fiber reinforced concrete shows enhanced strength than mono fiber reinforced concrete.

The present invention discusses a composite concrete mix composition comprising: an admixture of chemical admixture, powder content further including cement , SF and MK of 455, 53.5 and 26.75, FA of 589, CA of 1219 along with OPC, fiber percentage including ramie fibers and steel fibers varying between 0.5 to 2 % by weight where the total volume of the fibers is coming to 1 to 4 % of the total volume wherein the w/c ratio is 0.26.

The method of preparation includes steps of :
a. Preparation of cement (binder), coarse aggregates (CA), M-sand, Mineral admixtures (silica fume and metakaolin), super plasticizers, ramie fibers and hooked end steel fibers
b. Mixing the materials appropriately,
c. Casting
d. Curing

BRIEF DESCRIPTION OF THE DRAWINGS
Fig 1 Illustrating the compressive strength at 28 days
Fig 2 Illustrating the flexural strength at 28 days
Fig 3 Illustrating compressive strength
Fig 4 Illustrating the slump test results
Fig 5 Illustrating the Vee-bee Consistometer test results
Fig 6 Illustrating the Compaction Factor test results
Fig 7 Illustrating the .(a) Optical Photograph of CC (0% RF + 0% SF) (b) Optical Photograph of HFRC-1 (0.5% RF + 0.5% SF) for M70 Grade
Fig 8 Illustrating the Different steps in methods of Preparation of composite concrete mix

DETAILED DESCRIPTION OF THE INVENTION
The principles of operation, design configurations and evaluation values in these non-limiting examples can be varied and are merely cited to illustrate at least one embodiment of the invention, without limiting the scope thereof.

The embodiments will be described in detail with corresponding marked references to the drawings, in which the illustrative components of the invention are outlined. The embodiments disclosed herein can be expressed in different forms and should not be considered as limited to the listed embodiments in the disclosed invention. The various embodiments outlined in the subsequent sections are construed such that it provides a complete and a thorough understanding of the disclosed invention, by clearly describing the scope of the invention, for those skilled in the art.

Ramie fibers and Hooked-end steel fibers reinforced concrete are more effective compared to the conventional systems, the present invention provides a composite concrete mixture which is more resistances to cracks and corrosion and more tensile and flexural strength. It shows enhanced flexural strength and higher durability in applications such as decks, bridges etc., cracks resisting ability is increased up to four times than Conventional concrete as shown in figure 3 .Ramie and hooked-end steel fibers were utilized in different proportions.

In order to determine the fresh properties of the fiber reinforced concrete specimens, slump test, vee-bee consistometer test and compaction factor test were used. The test results of the same are provided in Fig-4,5,& 6. Higher fiber presence slightly (3.-5%, based on the fiber presence) reduces the fresh concrete properties. In order to examine the mechanical properties of the concrete specimens, compressive strength, split tensile strength, flexural strength, modulus of elasticity and impact test were used.

Further to examine the durability performances of the concrete specimens, water absorption test, absorptivity test, acid attack test, sulphate attack test, artificial marine attack test were conducted at various intervals.
For artificial marine attack test, marine solutions were prepared in the laboratory and in that concrete samples were immersed. In order to examine the morphological properties of the concrete specimens, SEM (Scanning Electron Microscope) test and XRF were conducted. SEM was conducted at Pondicherry technological university and XRF were conducted at Center for Earth science studies, Trivandrum, Kerala. Optical photograph analysis were did in order to identify the position of used materials, ITZ and a bonding between the used fibers and the materials.

HFRC is generally more ductile and suitable for concrete structures, which exhibits:
 Higher flexural strength, shear strength and tensile strength.
 High resistivity towards temperature.
 Higher resistance towards cracks initiation and formations.
 High durability and has more impact strength.
 Controlled concrete shrinkage.
 Ramie fibers has the resistances to bacteria, insect's attacks. (Natural fibers types).

Method of composite formation includes steps of process of ramie fiber extraction, inclusion of the same to provide hybrid form resulting in high strength in terms of mechanical and durability properties. Ramie fibers exhibit high strength during wet condition. In order to examine the mechanical properties of the concrete specimens, compressive strength test, flexural test, split tensile strength test, modulus of elasticity test and impact test were done. In order to examine the durability properties of the concrete specimens, water absorption test, absorptivity test, drying shrinkage, Acid attack test, sulphate attack test was done. High strength was obtained in both mechanical and durability performances. Minimum water absorption indirectly represents the absence of voids.

The results of the tests suggest that
• Compressive Strength was increased and improvement was in the range of 20 to 25% when compared to the plain specimen.
• Split Tensile Strength was increased and improvement was in the range of 10 to 15% when compared to the plain specimen.
• Flexural Strength was increased and improvement was in the range of 10.5 to 13.5% when compared to the plain specimen.
• Modulus of elasticity was increased and improvement was in the range of 15 to 20% when compared to the plain specimen.
• Impact resistance, ductility index was also increased and the number of blows for the initial cracks and ultimate cracks also increases when the fiber content increases.
• Water absorption was reduced and improvement was in the range of 15 to 18% when compared to the plain specimen.
• Drying shrinkage was reduced and improvement was in the range of 25 to 30% when compared to the plain specimen.
• In acid attack test, Weight loss and compressive strength loss was reduced and improvement was in the range of 10 to 15% and 19 to 25% when compared to the plain specimen respectively.
• In artificial marine attack test, Weight loss and compressive strength loss was reduced and improvement was in the range of 15 to 19% and 14 to 20% when compared to the plain specimen respectively.
• Optical photograph analysis was studied and new ITZ was studied. This is by way of photographic analysis and is shown in figure 7. From this analysis, a new Interfacial transition zone was formed between the cement paste and the aggregates as shown in figure.1.Utilization of natural fibers and treated recycled coarse aggregates makes a concrete as an eco-friendly material and there is a more chances to attain sustainable development.

Method of preparation ( as shown in figure 8)
a. Preparation of cement (binder), coarse aggregates (CA), M-sand, Mineral admixtures (silica fume and metakaolin), super plasticizers, ramie fibers and hooked end steel fibers
b. Mixing the materials appropriately,
c. Casting
d. Curing
The present invention discusses a composite composition comprising ramie fiber, hooked end steel fibers along with OPC and aggregates in specific ratio to provide a reinforced concrete mix with additional mechanical and durable properties.



MIX ID
W/C ratio
Chemical admixture
(silica fume & metakaolin)
Water Powder Content
FA
CA Fiber Percentage Total Volume of Fibers
Cement SF MK Ramie
Fibers Steel fibers
CC 0.26 2.67 141 455 53.5 26.75 589 1219 0 0 0
HFRC1 0.26 2.67 141 455 53.5 26.75 589 1219 0.5 0.5 1
HFRC2 0.26 2.67 141 455 53.5 26.75 589 1219 0.5 1 1.5
HFRC3 0.26 2.67 141 455 53.5 26.75 589 1219 0.5 1.5 2
HFRC4 0.26 2.67 141 455 53.5 26.75 589 1219 0.5 2 2.5
HFRC5 0.26 2.67 141 455 53.5 26.75 589 1219 1 0.5 1.5
HFRC6 0.26 2.67 141 455 53.5 26.75 589 1219 1 1 2
HFRC7 0.26 2.67 141 455 53.5 26.75 589 1219 1 1.5 2.5
HFRC8 0.26 2.67 141 455 53.5 26.75 589 1219 1 2 3
HFRC9 0.26 2.67 141 455 53.5 26.75 589 1219 1.5 0.5 2
HFRC10 0.26 2.67 141 455 53.5 26.75 589 1219 1.5 1 2.5
HFRC11 0.26 2.67 141 455 53.5 26.75 589 1219 1.5 1.5 3
HFRC12 0.26 2.67 141 455 53.5 26.75 589 1219 1.5 2 3.5
HFRC13 0.26 2.67 141 455 53.5 26.75 589 1219 2 0.5 2.5
HFRC14 0.26 2.67 141 455 53.5 26.75 589 1219 2 1 3


Due to the synergistic effects of fibers in hybrid form enhances the performances of the concrete specimens. Concrete is generally weak in tension but strong in compression and to some extensions by inclusions of a sufficient volume of certain fiber the weakness in tension may overcome. In general, adding fibers into concrete can effectively improve the tension-compression ratio of concreteas shown in figure 1 and 2 respectively. that is its tensile strength, flexural, toughness and improve its brittle failure characteristics. Durability of the structures can be improved obviously by adding ramie fibers into the concrete. Hybrid fibers of two types of fibers can complement each other's advantages and better play the "Positive hybrid effect ". Hybrid fiber reinforced concrete (HFRC) is a concrete with composite structure consisting of materials such as cement, M-Sand, Coarse aggregate, Ramie fibers, Hooked-end steel fibers along with admixtures and water. Novelty: Till now, this fiber combination is not used in prior research and our current research results shows that this fibers combination is too good in resulting good strength.

Industrial Applications include:
Inclusions of ramie fibers and hooked-end steel fibers in the concrete mix enhances the impact strength along with tensile strength of the materials. Above said combinations is not yet used in structural constructions, in hybrid form these combinations is less in cost. The invention has the excellent advantage of resistance towards cracks initiation, formations and towards corrosion. It is highly used in Bridges, roadways, shotcrete applications, high-rise buildings, sewer systems. These combinations in concrete incorporates the plasticity, elasticity and post-fractural behavior that validates the 3-point bending results which can be used for parametric studies. By the utilization of natural fibers in concrete creates a way to make an eco-friendly environment and sustainable development.

 
, Claims:WE CLAIM

1. A composite concrete mixture composition comprising:
chemical admixture of
powder content further including cement , SF and MK of 455, 53.5 and 26.75,
FA of 589,
CA of 1219,
OPC,
fiber percentage including ramie fibers and steel fibers varying between 0.5 to 2 % by weight where the total volume of the fibers is coming to 1 to 4 % of the total volume
wherein the w/c ratio is 0.26.

2. The composite concrete mixture composition as claimed in claim 1 wherein the improved compressive strength is increased by 20-25%.

3. The composite concrete mixture composition as claimed in claim 1 wherein the split tensile strength is improved by 10-15%.

4. The composite concrete mixture composition as claimed in claim 1 wherein the flexural strength is improved by 10-13.5%.

5. The composite concrete mixture composition as claimed in claim 1 wherein the modulus of elasticity is improved by 15 -20%.
6. The composite concrete mixture composition as claimed in claim 1 wherein the water absorption is reduced by 15-18%.

7. The method of preparation of composite concrete mixture includes the steps of :
a. Preparation of cement (binder), coarse aggregates (CA), M-sand, Mineral admixtures (silica fume and metakaolin), super plasticizers, ramie fibers and hooked end steel fibers
b. Mixing the materials appropriately,
c. Casting
d. Curing

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