CSIR-AMPRI has been working on developing materials for shielding from X-Ray, Gamma and Neutron radiation with application in various sectors ranging from X-Ray diagnostic centre to Nuclear Power plants. The group of dedicated scientists and technical staff with supporting staff and AcSIR students to form a strong multi disciplinary team from Physics, Chemistry, Chemical Engineering and Civil Engineering. The materials are made from industry waste like Fly-Ash, Red Mud and other industrial wastes by using unique Geo-polymerization processing to form advanced shielding phases and also having good mechanical strength. Some of the ongoing projects are described below;
Development of Fly Ash based Advanced Lingo-Silico-Aluminious (LSA) Geopolymeric Binder useful for Making Cement Free Green Concrete
R&D Project Summary:
- Ligno Silico (LS) alkaline activator was developed using agro waste i.e. rice husk and alkaline chemical.
- Developed LS Alkaline Activator was used for the preparation of Ligno-Silico-Aluminious (LSA) based Geopolymer concrete for which various mix design was developed by varying the ratio of LS Alkaline Activator/Fly Ash,. All cubes were thermally cured at 60 ◦C for 48 h and maximum compressive strength obtained was 30.8 MPa at 0.47 ratio after 28days.
- For the development of different grades of concrete were developed and as a result by changing the molarity of LS Alkaline Activator the different grades of concrete were developed using LS Solution M15, M20 and M25 LSA Geopolymer concrete was developed for both ambient and thermal cured conditions and for optimized composition flexural beam was casted and tested at 28 days as a result flexural strength of 3.4MPa, 4.5MPa and 5.2MPa was obtained at 8.75, 11.25 and 12.5 Molar LS solution.
- The cubes and beams were casted at different temperature ranging from 30 to 150 oC using optimized LS alkaline activator for the curing period of 48 h and maximum compressive strength obtained at 120 ◦C i.e. 46.3 MPa and for flexural maximum strength obtained at 120 oC i.e. 7.75MPa at 28days.
Evaluation of engineering properties of Ligno-Silico-Aluminious (LSA) based Geopolymer Concrete
Demonstration of Advanced LSA based Geopolymer Concrete Paver Blocks in front of workshop at CSIR-AMPRI
Bulk Uilitization of Red Mud for Making Advanced Ligno-Silico-Aluminious (LSA) Geopolymeric Materials
Red Mud is a solid waste produced in the process of alumina production from bauxite following the Bayer process. Depending on the raw material processed 1.0 – 2.5 tons of red mud is generated for every ton of alumina produced. More than 5 million tons of red mud is generated annually in India only. Presently, it is dumped on land near alumina refineries. However its high alkalinity is a potential pollution threat for water, and high costs are associated with the large area of land required for storage of the residue. India is amongest the major producers of alumina in the world. Significant achievements in treatment and utilization of red mud mud have been made in India in the last decade. Now there is an urgent need for bulk utilization of red mud in India.
CSIR-AMPRI, Bhopal proposed to carryout the project activity by utilizing huge availability of red mud and fly ash through a wider spectrum potential in the form of geopolymeric approach. This will find application in development of redmud-fly ash based advanced lingo-silico-aluminious (LSA) geopolymeric binder. The aim of our work is to define the most favorable conditions enabling the utilization of the geopolymerization process in the development of construction materials based on red mud using fly ash. On the basis of results the optimal conditions for geopolymerisation and the effect of the main synthesis parameters would be determined with respect to satisfactory mechanical and other properties of the developed LSA geopolymeric materials. The developed inorganic polymeric materials produced by the geopolymerization of red mud using fly ash would develop satisfactory compressive strength leading to use of these materials for construction industry. This will ensure the bulk utilization of two industrial waste namely red mud and fly ash.
Advanced (Cement Free) Solid form Geopolymer Binder based Concrete Rigid Pavement Road, at All India Institute of Medical Science (AIIMS)
A cement free Pavement Quality Green Concrete road of dimension 23 x 3.5 x 0.11 m, was constructed at AIIMS Bhopal for demostration. The following engineering properties i.e. Density: 2400 – 2600 Kg/m3, Compressive Strength: 35 MPa, Flexural Strength: 4.0 MPa, Slump: 110-120 mm. Four tonnes of Fly ash and 8.85 m3 cement free concrete was used for construction of the road. The road was ready to use after a week.
Advantages As Compared to Conventional Cement Concrete Road:
- Industrial waste utilized for this road
- Obviates the need of Water Curing
- Road gets “Ready for Use” within a Week
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Demonstration of Cement Free Geopolymer Concrete at AIIMS Bhopal
R & D studies on development of advanced geopolymeric coating materials for protection of corrosion of mild steel reinforcement used in concrete structures
Mild steel is used as structural steel in pipes, wire, marine applications, nuclear powered transportation, reinforcement, fencing, metal-processing equipments etc. all over the world. It is subjected to adverse environmental conditions which causes corrosion of and resulting in decrease in life of mild steel based structures. In order to address this problem, research is in progress all over the world for development of advanced coating materials with improved properties of corrosion resistance and adhesion to the parent surface. Geopolymers, which are alkali activated amorphous to semi crystalline alumino silicate materials are widely studied in recent years as coating materials. In the present work, different compositions of phosphatic geopolymeric coating material were developed utilizing fly ash, red mud, metakaolin, phosphate and other additives by novel process and coated on mild steel plates by dip, spray and paint brush coating techniques. Coated mild steel plates were tested for adhesion strength, high temperature resistance, fire resistance, and water resistance and corrosion resistance properties. Coated mild steel plates indicated adhesion strength upto 3.5 MPa and coating is found to be stable upto 500 °C. Developed coating material compositions were tested for corrosion resistance properties by weight loss method using 3.5 % NaCl. Corrosion protection efficiency of coated mill steel plates was found to be 80 to 85 % and corrosion rate is 2-3 times lower than uncoated mild steel. Electrochemical measurements were performed for testing of corrosion resistance using an anodic polarization method. The small passage of current through geopolymer coated mild steel plates confirms the strong resistance of the coated materials towards corrosion. Accelerated corrosion test was performed in salt spray chamber. Onset of corrosion started after 20 -22 hours confirms again the strong resistance of the coated materials towards corrosion.
Geopolymer coated mild steel tubes and Plate
X-ray diffraction pattern of coating compositions indicated presence of geopolymeric phases like sodium silicate and hydrated sodium aluminium silicate. SEM images indicated strong binding of the coating material on the surface (mild steel). Results indicated that developed coating material possess promising corrosion resistance characteristics. Further studies on development of novel coating material compositions with improved adhesion strength and corrosion protection characteristics are under progress.
Feasibility study and process development on the conversion of fly / pond ash into Fine aggregate
- PROJECT OBJECTIVE– The main objective of the project is to convert both Fly ash as well as Pond ash into fine aggregates using geopolymeric route. The R&D Study will be a single step solution to both environment as well as fast depleting river sand.
- Concrete is the most used constructional material across the world and in concrete, maximum part is fine aggregate. On one side large scale utilization of limited river sand resources and imposition of restrictions on river sand supply has forced for finding an alternative, on the other side large quantity of coal ash is being produced every day in Thermal Power plants, leading to many environmental problems. Coal ash utilization will help to reduce the consumption of natural resources. Pond ash being coarser and less pozzolanic is generally not being used in construction industries. The studies will also include use of pond ash for conversion into fine aggregates.
Detailed Methodology
- Chemical reaction mechanism (variation in time and temperature)
- Role of materials (variation in components and concentration)
- Characterization of developed material
- Comparative study between geopolymeric sand and conventional sand (chemical and civil property as per Indian standard)
- Optimizing the parameters. Full / part replacement of river sand with synthetic sand obtained from pond/fly ash.
ANTICIPATED BENEFITS: The study will help to reduce the demand of natural sand, fly ash related environmental problems, landfill area requirement and contribute towards energy conservation. The work is to focus on enhancing fly ash utilization rate to maximum extent in a gainful way.
Fine aggregates (sand sized) prepared by fly ash