Novel Multifunctional Material for Workability of Geopolymeric System and its Process Thereof

Abstract

The present invention relates to a novel multifunctional material for workability of geopolymeric system and its process thereof. The viscous characteristics in geopolymeric system are responsible for observed negligible workability of geopolymeric cement concrete system and which limits its broad application spectrum. The novel multifunctional material of the present invention prepared by digestion of siliceous agricultural waste i.e. Rice husk with aqueous alkaline materials involving simultaneous and synergistic chemical reactions among the various constituents of rice husk, aqueous alkaline compounds and optionally adding Cetyl trimethyl ammonium bromide (CTAB) to obtain in-situ synthesis of desired nano-sized multi functional agents lignin, hemicelluloses, cellulose, sodium silicate necessary for addressing the issue of workability and also improving the engineering properties of geopolymeric system for broad application spectrum.

Claims

1. A novel multifunctional material for addressing the issue of workability of geopolymeric system comprising: rice husk in the range of 6.2% to 8.5%, NaOH in the range of 1.7% to 31%, and optionally CTAB in the range of 0.62% to 0.85% and water in the range of 60 to 92%.

2. A novel multifunctional material as claimed in claim 1, wherein the material possesses following properties: i) pH=14 ii) viscosity in the range of 7 mPa.Math.s to 11 mPa.Math.s

3. A process for preparation of novel multifunctional material as claimed in claim 1, comprising steps of: a) digesting rice husk in the range of 6.2% to 8.5%, NaOH in the range of 1.7% to 31%, and optionally CTAB in the range of 0.62% to 0.85% in water in the range of 62% to 85% at a temperature in the range of 50° C. to 100° C. for a period in the range of 3 to 14 hours to obtain digested mass, b) filtering the digested mass of step a) to obtain the slurry of multi-functional material in the range of 50% to 80% containing various functional constituents lignin, hemicelluloses, cellulose, sodium silicate in desired nano size in the range of 40 to 100 nm, morphology and chemical architecture.

4. The process as claimed in claim 3, wherein the preferable temperature range is 60° C. to 90° C., and time period 4 to 12 hours.

5. A process for the preparation of geopolymeric mortar/concrete cubes using novel multifunctional material system as claimed in claim 1, comprising the steps of: a) adding 0.25 to 1.5% slurry of multifunctional material as obtained in step b) of claim 3 with respect to fly ash in the standard geopolymeric mortar/ concrete mix and water and casting mortar/concrete cubes by known method, b) curing the said mortar/concrete cubes at a temperature in the range of 40 to 60° C. for a period in the range of 46 to 50 hrs to obtain finished geopolymeric mortar/concrete cubes.

6. A process as claimed in claim 5, wherein geopolymeric mortar cubes are obtained when slurry of multifunctional material is mixed with standard geopolymeric mortar comprising fly ash, sodium hydroxide, sodium meta silicate and water.

7. A process as claimed in claim 5, wherein geopolymeric concrete cubes are obtained when slurry of multifunctional material is mixed with standard geopolymeric concrete comprising fly ash, sodium hydroxide, sodium meta silicate , coarse aggregate and fine aggregates and water.

8. A process as claimed in claim 5, wherein geopolymeric mortar/concrete cubes posses compressive strength in the range of 25 to 60 MPa.

9. A process as claimed in claim 5, wherein mortar/concrete cubes being casted in the dimension of 7.06 cm×7.06 cm×7.06 cm and 15 cm×15 cm×15 cm.

10. A process as claimed in claim 5, wherein preferable curing time period is 48 hrs.

Description

DETAILED DESCRIPTION

[0090] The invention provides a novel process obviating the need of one of the important raw material that is sodium silicate as the chemical reaction among the raw material is designed in such a way that process mechanism enables in-situ synthesis of sodium silicate otherwise necessarily required to be added externally.

[0091] The invention also describes in providing: [0092] i) the hemicellulose in the form of sodium lignate responsible for improving the mechanical properties and modifying the viscosity and also acts as a gelling agent, [0093] ii) the cellulose in the fibrous form which is providing reinforcement and thus also responsible for improving the mechanical properties, modifying the viscosity and also acts as a binding agent, [0094] iii) the alkaline multifunctional agents imparting excellent thermal stability and therefore it is useful for providing heat resistant properties to the developed geopolymeric matrix.

[0095] The process flow sheet for making multifunctional material is as mentioned below:

[0096] The following examples are given by way of illustration of the working of the invention in actual practice and therefore should not be construed to limit the scope of the present invention in any way.

EXAMPLE—1 Preparation of Novel Multifunctional Material

[0097] For the preparation of novel multifunctional material 100 g rice husk, 500 g NaOH, 10 g CTAB was digested in 1000 ml water at the temperature of 60° C. for the duration of 4 hours and the digested mass was filtered using 45 micron sieves to obtain the 500 ml slurry of multi-functional material. The pH and viscosity of the material was found to be 14 and 7.3 mPa.Math.s

EXAMPLE—2 Preparation of Novel Multifunctional Material

[0098] For the preparation of novel multifunctional material 500 g rice husk, 2500 g NaOH, 50 g CTAB was digested in 5000 ml water at the temperature of 90° C. for the duration of 12 hours and the digested mass was filtered using 45 micron sieves to obtain the 2500 ml slurry of multi-functional material. The pH and viscosity of the material was found to be 14 and 9.5 mPa.Math.s

EXAMPLE 3: Workability/Utilization of Novel Multifunctional Material

[0099] For addressing the workability of standard geopolymeric system 0.25% slurry of multifunctional materials with respect to fly ash present in the standard geopolymeric mortar was added to the design mix comprising of 250 g fly ash, 500 g sand, 33 g of sodium hydroxide,16.5 g of sodium meta silicate and 66 ml of water and the mortar cubes were casted in the dimensions of 7.06 cm×7.06 cm×7.06 cm using standard methods and were heat cured in the temperature range of 40° C. for a duration of 48 hours and mortar were tested for 1) change in workability by flow table test with respect to controlled mix possessing slump value 100 mm and found to be 107 mm for when slurry of 0.25% were added 2) cubes were tested for compressive strength as per Indian Standard method of test for 3,7 and 14 days and found to possess compressive strength of 35.8 MPa, 37.7 MPa and 39.2 MPa respectively for geopolymeric mortar cubes.

EXAMPLE 4: Workability/Utilization of Novel Multifunctional Material

[0100] For addressing the workability of standard geopolymeric system 0.50% (10% CTAB) containing slurry of multifunctional materials with respect to fly ash present in the standard geopolymeric mortar was added to the design mix comprising of 250 g fly ash, 500 g sand, 33 g of sodium hydroxide, 16.5 g of sodium meta silicate and 66 ml of water and the mortar cubes were casted in the dimensions of 7.06 cm×7.06 cm×7.06 cm using standard methods and were heat cured in the temperature range of 40° C. for a duration of 48 hours and mortar were tested for 1) change in workability by flow table test with respect to controlled mix possessing slump value 100 mm and found to be 113 mm for when slurry of 0.50% were added 2) cubes were tested for compressive strength as per Indian Standard method of test for 3, 7 and 14 days and found to possess compressive strength of 38.7 MPa, 39.5 MPa and 40.3 MPa respectively for geopolymeric mortar cubes.

EXAMPLE 5: Workability/Utilization of Novel Multifunctional Material

[0101] For addressing the workability of standard geopolymeric system 1% slurry of multifunctional materials with respect to fly ash present in the standard geopolymeric mortar was added to the design mix comprising of 250 g fly ash, 500 g sand, 33 g of sodium hydroxide, 16.5 g of sodium meta silicate and 66 ml of water and the mortar cubes were casted in the dimensions of 7.06 cm×7.06 cm×7.06 cm using standard methods and were heat cured in the temperature range of 40° C. for a duration of 48 hours and mortar were tested for 1) change in workability by flow table test with respect to controlled mix possessing slump value 100 mm and found to be 133 mm for when slurry of 1% were added 2) cubes were tested for compressive strength as per Indian Standard method of test for 3, 7 and 14 days and found to possess compressive strength of 39.1 MPa, 41.5 MPa and 50.6 MPa respectively for geopolymeric mortar cubes.

EXAMPLE 6: Workability/Utilization of Novel Multifunctional Material

[0102] For addressing the workability of standard geopolymeric system 1.5% slurry of multifunctional materials with respect to fly ash present in the standard geopolymeric mortar was added to the design mix comprising of 250 g fly ash, 500 g sand, 33 g of sodium hydroxide, 16.5 g of sodium meta silicate and 66 ml of water and the mortar cubes were casted in the dimensions of 7.06 cm×7.06 cm×7.06 cm using standard methods and were heat cured in the temperature range of 40° C. for a duration of 48 hours and mortar were tested for 1) change in workability by flow table test with respect to controlled mix possessing slump value 100 mm and found to be 140 mm for when slurry of 1.5% were added 2) cubes were tested for compressive strength as per Indian Standard method of test for 3, 7 and 14 days and found to possess compressive strength of 41.5 MPa, 44.7 MPa and 47.2 MPa respectively for geopolymeric mortar cubes.

EXAMPLE 7: Workability/Utilization of Novel Multifunctional Material

[0103] For addressing the workability of standard geopolymeric system 0.50% slurry of multifunctional materials with respect to fly ash present in the standard geopolymeric concrete was added to the design mix comprising of 1.5 kg fly ash, 0.213 kg sodium hydroxide, 0.106 kg sodium meta silicate, 5 kg coarse aggregate, 2.5 kg fine aggregates and 0.462 I of water and the mortar cubes were casted in the dimensions of 15 cm×15 cm×15 cm using standard methods and were heat cured in the temperature range of 60° C. for a duration of 48 hours and were tested for 1) change in workability by measuring the slump with respect to controlled mix possessing slump value 150 mm and found to be 170 mm for when slurry of 0.50% were added 2) were tested for compressive strength as per Indian Standard method of test for 3, 7, 14 days and 28 days and found to possess compressive strength of 46.1 MPa, 48.2 MPa, 51.4 MPa and 58.1 MPa respectively for geopolymeric concrete cubes.

EXAMPLE 8: Workability/Utilization of Novel Multifunctional Material

[0104] For addressing the workability of standard geopolymeric system 0.25% slurry of multifunctional materials with respect to fly ash present in the standard geopolymeric concrete was added to the design mix comprising of 1.5 kg fly ash, 0.213 kg sodium hydroxide, 0.106 kg sodium meta silicate, 5 kg coarse aggregate, 2.5 kg fine aggregates and 0.462 l of water and the mortar cubes were casted in the dimensions of 15 cm×15 cm×15 cm using standard methods and were heat cured in the temperature range of 60° C. for a duration of 48 hours and were tested for 1) change in workability by measuring the slump with respect to controlled mix possessing slump value 150 mm and found to be 160 mm for when slurry of 0.25% were added 2) were tested for compressive strength as as per Indian Standard method of test for 3, 7, 14 days and 28 days and found to possess compressive strength of 25.9 MPa, 26.1 MPa, 26.0 MPa and 30.9 MPa respectively for geopolymeric concrete cubes.

[0105] Advantages of the present invention include: [0106] i) unique designing of chemical reactions among the raw materials to obtain the nano size multi functional agents Lignin, hemicelluloses, cellulose, sodium silicate simultaneously and in desired proportions by controlling the a) temperature range b) reaction duration c) ratios of raw materials and d) molarity of the reaction solutions during the synthesis of desired multifunctional material. [0107] ii) total utilization of rice husk waste. [0108] iii) A low temperature and energy efficient process for making novel multifunctional material for addressing the issue of workability of geopolymeric system. [0109] iv) to develop a novel process obviating the need of one of the important raw material that is sodium silicate as the chemical reaction among the raw material is designed in such a way that process mechanism enables in-situ synthesis of sodium silicate otherwise necessarily required to be added externally. [0110] v) providing the hemicellulose in the form of sodium lignate responsible for improving the mechanical properties and modifying the viscosity and also acts as a gelling agent. [0111] vi) providing the cellulose in the fibrous form which is providing reinforcement and thus also responsible for improving the mechanical properties, modifying the viscosity and also acts as a binding agent. [0112] vii) to develop the alkaline multifunctional agents imparting excellent thermal stability and therefore it is useful for providing heat resistant properties to the developed geopolymeric matrix.