Abstract Concrete is most used construction material. enhance the strength to the concrete. Fibers act as crack

Transcription

1 MECHANICAL PROPERTIES OF BASALT FIBER BASED GEOPOLYMER CONCRETE K.Arunagiri 1, P.Elanchezhiyan 2, V.Marimuthu 3 G.Arunkumar 4 and P.Rajeswaran 5 UG Students, Department of Civil Engineering, Sethu Institute of Technology, Pulloor, Kariapatti, Tamil Nadu, India 1,2,3,4 Assistant Professor, Department of Civil Engineering, Sethu Institute of Technology, Pulloor, Kariapatti, Tamil Nadu, India 5 Abstract Concrete is most used construction material. enhance the strength to the concrete. Fibers act as crack Construction industry uses most of the natural resources as it arrestors in concrete. The different types of fibers used in includes production of cement. It is the major contributing concrete are steel fibers, basalt fibers, glass fibers factor to the CO2 emission, causing global warming. An polypropylene fibers. alternate to the OPC has been found out known as geopolymer concrete. It uses industrial waste material such as fly ash and 2. Experimental Materials GGBS instead of cement thereby decreasing impacts due to 2.1 Materials cement production. In this study both fly ash and GGBS are utilized in making Geopolymer concrete. Alkaline solution Fly ash is the aluminosilicate source materials used for the synthesis of geopolymeric binder. In this study, low used is comprises of sodium silicate and Sodium hydroxide in calcium fly ash (ASTM Class-F) obtained from the Tuticorin the ratio of 2.5.sodium hydroxide of 8 molarity is used. Plain thermal power plant and GGBS obtained from Mangalore concrete is weaker in tension. Fibers are added to enhance the were utilized as the source materials. Fine aggregate is sieved strength to the concrete to meet given serviceability using 4.75mm sieve to remove all the pebbles. Specific gravity requirements. Basalt fiber is considered a promising new of fine aggregate is 2.81 and its fineness modulus is It material it has good strength characteristics, resistance to confirms zone II of IS requirements. Specific chemical attack, sound insulation properties. It has wide range gravity of coarse aggregate is 2.73 and its fineness modulus is 7. In this investigation, a combination of sodium hydroxide of applications like soil strengthening, construction of bridges, and sodium silicate solution was used as alkaline activators for highways, industrial floors. In present experimental geopolymerisation. Sodium hydroxide is available investigation various proportions of basalt fibers added to the commercially in flakes or pellets form. Table 1 shows the geopolymer concrete the compressive, split tensile and physical properties of these binders. Similarly Table 2 shows flexural strengths were investigated. All the strength compare to with and without addition of basalt fibers. The basalt fibers are added to the geopolymer concrete in the range of 0.5%, the chemical properties of these binders. Table 1Physical properties of binders 1%, 1.5%, 2% and 2.5% at 0.5% increments. it is concluded S.No. Property Fly ash GGBS that the percentage of basalt fibers increases and also increase 1 Specific gravity compressive, split tensile and flexural strength upto 2%. 2 Fineness modulus Keywords Geopolymer concrete, Fly fiber,alkaline liquid, Strength. ash, GGBS, Basalt Table 2 Chemical properties of binders (%) 1. Introduction Concrete is the most utilized construction material around the world. It uses cement, fine aggregate and coarse aggregate as its constituents. Because of its extensive use the consumption of cement is increasing now days. Portland cement production is major contributing factor to the Carbon- die-oxide emissions, this causes global warming. So an alternate to the ordinary Portland cement has been developed and known as Geopolymer concrete. It uses waste material such as fly ash, blast furnace slag to produce concrete. Plain Geopolymer concrete is weak in tension, because of concrete hold aggregates can crack, and cause concrete to break. Different type of fibers is added to the concrete to Binders SiO2 Al2O3 Fe2O 3 CaO MgO Na2O LOI Fly ash GGBS Basalt Fibers Basalt is a volcanic rock and can be chopped into small particles then formed into continues or chopped fibers. Basalt fiber has a higher working temperature and has a good resistance to chemical attack, impact load, and fire with less poisonous fumes. These fibers are used in wide range of applications such as strengthening of soils, construction of highways, bridges and industrial floors, retrofitting activities etc. Table 3 shows the properties of basalt fiber. 551

2 Table -3: Properties of basalt fibers Properties Value 2630 kg/m 3 Density Tensile strength M Pa Elastic modulus G Pa Elongation at break 3.1 % 10500C Softening point C Working temperature Thermal conductivity W/m-K 3. Design Mix density of concrete the amount of binder, fine aggregate and quantity of alkaline liquids was determined. The morality of sodium hydroxide concentration is kept as 8M. The different parameter considered in this study is proportion of fine aggregate components. The ratio of Na2SiO 3/NaOH solutions and alkaline liquid to binder ratio is kept constant. The ratio of Na2SiO 3/NaOH solutions is taken as 2.5 & alkaline liquid to binder ratio as Extra water was added 10% by weight of cementitious material to get desirable workability for all the mixes. Table 4 shows the mix proportion for alkaline liquid to binder ratio Mix Proportion The density of geopolymer concrete is 2400 kg/m 3.The alkaline liquid to binder ratio as 0.45 and by knowing the Proportions Fly ash GGBS Of basalt Fiber F G B NaOH Na2SiO3 C.A Basalt fiber 3 (kg/m 0 ) Sand F80G 20B F80G 20B F80G 20B F80G 20B F80G 20B Fly ash Natural sand Basalt fiber GGBS Coarse Aggregate Na2SiO 3 NaOH Fig.1. Ingredients of geopolymer concrete 552

3 3.2 Mixing To prepare the 8 molarity concentration of sodium hydroxide solution, 320 grams (molarity x molecular weight) of sodium hydroxide flakes was dissolved in distilled water Sand makeup was done to one litre. The sodium hydroxide solution thus prepared is mixed with sodium silicate solution one day before mixing the mortar to get the desired alkaline solution. Distilled water is used to dissolve the sodium hydroxide flakes to avoid the effect of contaminants in the mixing water. The fly ash, GGBS, fine aggregate, coarse aggregate and basalt fiber was dry mixed before adding the alkaline solution. Sodium hydroxide is available commercially in flakes or pellets form. For this present study, sodium hydroxide flakes with 98% purity were used for the preparation of alkaline solution. Sodium silicate is available commercially in solution form and hence it can be used. Sodium silicate with Na2O = 14.7%, SiO 2 = 29.4% and water = 55.9% by mass was used in this research. Sodium hydroxide solution was used as alkaline activator because it is widely available and is less expensive than potassium hydroxide solution. 4. Experimental program 4.1Compressive Strength Test The compressive strength is the ratio of the maximum load to the surface area of the cube. Three cubes were tested for each mix ratio and the average of three specimens is taken as the compressive strength it was tested by compression testing machine of capacity 2000 kn. The geopolymer concrete were tested for compressive strength at the age of 7 day and 28 day. The specimens were subjected to a compressive force at the rate of 132kN per minute. Fig.3. and Fig.4. show the cubes under test and the concrete cube specimens, after testing respectively. 3.3 Preparation of Test Specimens Compressive strength was found out using cubes of standard size 150 mm x 150 mm x 150 mm. Totally 36 cubes were cast with 6 cubes for each mix ratio. Out of 36 cubes were used to find the compressive strength. After casting process, the specimens were kept for 24 hours and then demoulded. They were self cured at room temperature for 7 days and 28 days. Similarly the split tensile strength test carried for cylinder of size 150mm x 300mm. Fig.3. cube under test Fig.2 Geopolymer Concrete specimens different mix proportion made with 553

4 Fig.4. Concrete cube specimens after test Fig.6. Concrete cube specimens after test 4.3 Flexural strength 4.2 Split Tensile Strength Test The tensile strength on cylinder is conducted to the following procedure.the specimen is placed in compression testing machine and load is applied along diametrical ends. load is increased continuously until the specimen fails and note down the reading then find out the tensile strength.fig 5 shows the cylinder specimen under test. The flexural strength test was carried out as per IS 516: Prism concrete specimens 100 mm in width, 100 mm height and 500 mm in length were cast. The specimens were tested for flexural strength using universal testing machine at the age of 7 and 28 days.fig 6 shows the cylinder specimen under test. Fig 5 cylinder under test Fig 7. Beam specimen under test

5 5. RESULTS AND DISCUSSIONS 5.1 Compressive Strength Compressive strength of the cube was tested at 7 and 28 days,according to IS Table 5 shows the compressive strength results. Table 5 Compressive strength results Compressive Strength ( N/mm 2 ) At 7 days At 28 days Split Tensile Strength Split tensile strength of the cylinders at 7 and 28 days were tested to find the strength, according to IS Table 6 shows the split tensile strength results. Table 6 Split tensile strength results Split tensile Strength ( N/mm 2 ) At 7 days At 28 days Fig.8. 7 & 28 Days compressive strength of specimens The above figure shows the variation of compressive strength For different percentages of the basalt fibers. the compressive Strength of the reference mix is MPa.There is sudden increase in the compressive strength of about10% for 0.5% addition of fiber, After that addition of fiber increases the compressive strength in gradually small values, it reaches maximum value of 40 MPa for fiber content of 2%.after that value addition of fibers un alters the compressive strength. so 2% is fiber added for increase the compressive strength of GPC. Fig.9. 7 & 28 Days Split tensile strength of specimens The above figure shows the variation of tensile strength for different percentages of the basalt fibers. There is a increase in the compressive strength with the increased basalt content was observed. 555

6 5.3.Flexural strength Flexural strength of beam specimens were tested at 28 days Table7. Flexural Strength Results Flexural Strength (N/mm 2 ) At 28 Days References 1. Sangamesh Upasi, Sunil Kumar H.S, Manjunatha. H, Dr.K.B.Prakash, An investigation on strength characteristics of basalt fibre reinforced concrete, IJOER,Vol 2, issue 5, Vignesh.P,Vivek K, An Experimental Investigation On Strength Parameters Of Fly ash Based Geopolymer Concrete With GGBS,IRJET,Vol.2,May Abdul Aleem.M.I and Arumairaj.P.D, Optimum mix for the geopolymer concrete, IJST, Vol 5,March M. S. Shetty (A handbook of concrete technology ) 5. Kunal Singha, A Short Review on Basalt Fiber,International Journal of Textile Science 2012, 1(4): DOI: /j.textile Gore Ketan R, The Performance of Basalt Fibre in High Strength Concrete, Journal of Information, Knowledge and Research in Civil Engineering, ISSN: NOV 12 TO OCT 13 Volume 2, Issue 2 7..Faisal Fouad wafa, Properties and Applications of Fiber Reinforced Concrete, JKAU: Engineering Science, Vol.2,PP IS: Specification for Fly Ash for Use as Pozzolana and Admixture. 9. IS: Specification for Granulated Slag for the Manufacture of Portland Slag Cement. 10. IS: , Split tensile strength of concrete Method of test. Fig Days flexural strength of specimen 6. Conclusion 1. The maximum compressive strength of geopolymer concrete is obtained at 2% addition of basalt fiber. 2. It can be concluded at basalt fiber act as a crack arrestors and prevent sudden failure of structures. 3. It can be concluded at addition of basalt fiber at an optimum content to the geopolymer concrete can increase compressive as well as tensile strength. 4. Basalt fibers have no toxic reaction with air, water and alkaline solution. 5. Adding basalt fiber to concrete decreases amount of heat conducted through the thickness. 556