APPLICATIONS OF GEOPOLYMER IN BUILDING MATERIALS AND RETROFITTING

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1 APPLICATIONS OF GEOPOLYMER IN BUILDING MATERIALS AND RETROFITTING PROJECT REFERENCE NO. : 37S0126 COLLEGE : B.V.BHOOMARADDI COLLEGE OF ENGINEERING & TECHNOLOGY, HUBLI BRANCH : CIVIL ENGINEERING GUIDE : M.V.CHITAWADAGI STUDENTS : SANTOSH.C.SATALI KAVITA.S BASAVARAJ.M.M SURESH.B.MASANAGI Keywords: Geopolymer, Retrofitting, UCC (Unconfined Concrete Columns), EP-CFRP (Epoxy based wrapping), GP-CFRP (Geopolymer based wrapping). Introduction: Davidovits [1988] proposed that an alkaline liquid could be used to react with the silicon (Si) and the aluminium (Al) in a source material of geological origin or in by-product materials such as fly ash and rice husk ash to produce binders. Because the chemical reaction that takes place in this case is a polymerization process, he coined the term "Geopolymer to represent these binders. Research is shifting from the chemistry domain to engineering applications and commercial production of geopolymer concrete. Unlike ordinary Portland / Pozzolana cements, geopolymers do not form C-S-H gel (calcium-silicate-hydrates) for matrix formation and strength, but utilize the polycondensation of silica and alumina and a high alkali content to attain structural strength. There are two main constituents of geopolymers, namely the source materials and the alkaline liquids. The source materials for geopolymers based on alumina-silicate should be rich in silicon (Si) and aluminum (Al). These could be natural minerals such as kaolinite, clays, etc. 1

2 Alternatively, by-product materials such as fly ash, GGBS, silica fume, slag, rice-husk ash, red mud, etc can be used as source materials. The choice of the source materials for making geopolymers depends on factors such as availability, cost, type of application, and specific demand of the end users. The alkaline liquids are from soluble alkali metals that are usually sodium or potassium based. The most common alkaline liquid used in geopolymerization is a combination of sodium hydroxide (NaOH) or potassium hydroxide (KOH) and sodium silicate or potassium silicate. Objectives: Objectives of the project are summarized as follows: To achieve optimum mix proportion of geopolymer constituents to develop geopolymer tiles confirming to IS To investigate the suitability of a geopolymeric resin in an externally bonded composite system for strengthening of cement concrete cylinders of size 150 mm X 300 mm. Methodology Geopolymer tiles: The present study involves the manufacturing of geopolymer tiles using geopolymer. Geopolymer tiles of size 200mm x 200mm x 10 mm are cast. Flexural strength, water absorption, abrasion resistance of the tiles will be tested. Fig: Manufacturing of geopolymer tiles. 2

3 Retrofitting of concrete structures using gp (gp-frp): 22 PC cylinder of size 300x150 mm are casted. 2 cylinders will be used as control cylinders. 2 cylinders will be wrapped with CFRP using Epoxy resin. Remaining cylinders are wrapped with CFRP using Geopolymer. Results and Conclusions: Test results of geopolymer tiles: Tests on tiles: Modulus of rupture. Water absorption. Abrasion resistance. 1. Modulus of rupture: The values of modulus of rupture of tiles are shown in table 5.1.The tiles manufactured using different molarities of NaOH solution and solution-to-binder ratio are tested in testing machine and the values of breaking load are noted. Then the modulus of rupture is calculated using the above formula. It is found that for molarity 10M and solution-tobinder ratio 0.35 the modulus rupture of tile is 16.3 Mpa which is more than the required as per IS 13754: Water absorption test: The values of water absorption of tiles are shown in table 5.2.The dry weight of tiles are noted down and are kept in a container completely filled with water for 24 hours. And after 24 hours tile is taken out and weighed. Then the water absorption is calculated using the above formula. It is found that for molarity 10M and solution-to-binder ratio 0.35 the water absorption of tile is 7.23% which is in the range of 6-10% as specified in IS 13754:

4 3. Abrasion test: The values of abrasion resistance of tiles are shown in table 5.3.The loss in mass of specimens is noted down after the experiment. Then the loss in volume is calculated using the above formula. Abrasion resistance is expressed in terms of loss in volume. It is found that for molarity 10M and solution-to-binder ratio 0.35 the abrasion resistance of tile is 462 mm 3 which is less than 540 mm 3 as specified in IS 13754:1993. B) Test Results Of Retrofitting Of Column: Specimen Ultimate Axial Load (kn) Axial Shortening at Ultimate Axial load (mm) UCC EP-CFRP GP-CFRP Conclusion: Manufacturing process of geopolymer tiles is simple and easy compared to conventional tiles. Geopolymer tiles are cheaper than ceramic tiles. Cost of geopolymer tiles mainly depends on sodium silicate solution. Cost of geopolymer tiles can be further reduced by increasing the molarity of NaOH solution instead of increasing (sol/binder). Automatic surface finish is obtained during vibration. Extra water added to mixture is important parameter which governs the surface finish. Very sensitive to changes of chemical composition of Secondary raw materials and application in fields are restricted by the performance. The percentage increase in axial load for confined cylinders as compared to UCC 4

5 is 114.7% for a maximum axial shortening of 8.0 mm. There is no significant increase in axial load carrying capacity of cylinders wrapped with GP-CFRP due to the adverse climatic conditions. Scope for future work: Water absorption can be still reduced. The raw material (fly ash) properties need to be studied. Fine aggregates or quarry dust can be used. 5