STUDY BASIC PROPERTIES OF FIBER REINFORCED HIGH VOLUME FLY ASH CONCRETE

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1 Research Article STUDY BASIC PROPERTIES OF FIBER REINFORCED HIGH VOLUME FLY ASH CONCRETE 1 Prof.Indrajit Patel, 2 Dr.C D Modhera Address for Correspondence Applied Mechanics Department, B & B Institute of Technology, Vallabh Vidya Nagar, Gujarat, Professor, Department of Applied Mechanics, SVNIT, Surat, Gujarat, , inpatel34@gmail.com, cdm@svnit.ac.in ABSTRACT: The sustainability issue for concrete construction industry is not arrived due to one or more reasons related to the material or the technology itself. This includes it consumes large quantities of precious natural materials; the fundamental binder in concrete is cement, a significant contributor to greenhouse gas emissions that are implicated in global warming and climate change. Majority of concrete structures suffer from durability issues which have an adverse effect on the resource productivity of the industry. Use of industry waste like fly ash, silica fume, grounded furnace slag to partly replace cementing material concrete system addresses all three sustainability issues, its adoption will enable the concrete construction industry to become more sustainable. The use of high volume fly ash (HVFA) concrete opts in very well with sustainable development. High volume fly ash concrete mixtures contain lower quantities of cement and higher volume of fly ash (up to 60%). The use of fly ash in concrete at proportions ranging from 35 to 60% of total cementations binder has been studied extensively over the last twenty years and the properties of blended concrete are well documented. The replacement of fly ash as a cementations component in concrete depends upon several factors. The design strength and workability of the concrete, water demand and relative cost of fly ash compared to cement. From the literature it is generally found that fly ash content in the cementitious material varies from 30-80% for low strength (20MPa) to high strength (100MPa) Use of High Volume Fly Ash (HVFA) concrete is very popular in countries like Japan, Canada and other developed nation since last century but due to certain limitations of application area the same has been not popularize worldwide. The limitations include slower early strength development, poor resistance to impact and abrasion and contribution to flexural as well. KEY WORDS: High volume, Fly Ash, Polyester fibre, Workability, Compressive Strength 1. INTRODUCTION significant amount of glassy material in Use of supplementary cementing material in form industrial waste or by product contributes the sustainability issue for concrete technology. Fly ash being major product of thermal power station and possesses the required specifications it is widely use as supplement to cement. The pozzolanic action of fly ash is due to the particular and mineralogical composition in general. The particle size also governs the properties of fresh and hardens concrete. Particle size shape and texture along with chemical composition affect the water demand, workability, particle size distribution, particle packing effect and smoothness of surface texture of concrete.

2 Finer size particle generally less than 10u and physic-chemical effect due to presence of pozzolanic cementitious reaction causes pre size and grain size reduction phenomenon which ultimately results in improvement in mechanical and durability properties as well. Scope of the present work as a part of Ph.D. research work includes preparing trial and final design mix for HVFA containing 50,55,60% flyash for M25,M30,M35 and M40 grade of concrete. For improving the mechanical and durability properties of HVFA concrete 12 mm triangular shaped polyester fibre were added in proportion of 0.25 and 0.50% of cementing material by mass. Literature review has also been made for use of polyester fibre in normal concrete in terms of improvement in compressive and flexural strength, impact and abrasion resistance and resistance to alkaline condition. The paper includes final mix composition, test results of special concrete additives like flyash and polyester fibre. The part work presented in this paper also includes workability through slump test, and mechanical property by compression test of all designated mixes and comparative study is made for inclusion of polyester fibre in normal HVFA concrete. All the ingredients were procured from local sources, tested as per relevant standard and confirmed the same meeting required standards. The main purpose of this investigation is to develop confidence among user to use high volume fly ash concrete in all possible sectors of the building construction. 2. MATERIALS: 2.1 Cement and Fly ash: 53 grade Ordinary Portland cement conforming to B was used. Class F fly ash from Wanakbori Thermal Power station, Gujarat conforming to B was used in the present study. Its physical properties and chemical composition are given in table [1]. The scanning electron microscopic view of the fly ash is shown in the figure [1]. 2.2 Admixtures: High range water reducing admixtures based on Naphthalene sulfonate was used for preparation of trial mix and letter for plain HVFA concrete samples. Latter for fibre reinforced HVFA samples Poly Carboxylate based super plasticizer was used. 2.3 Aggregates: Crushed stones of 20mm down and 10mm

3 down were used as coarse aggregate. Local river sand was used as fine aggregate in the concrete mixtures. 2.4 Fiber: 12mm size triangular-trilobal shaped polyester fibre confirming to type III fibres under ASTM C: 1116 were used as a supplementary reinforcing material to enhance the mechanical properties of hardened concrete. The test results and microscopic view of the same is given in table [2] and figure [2] respectively. Sr. No Characteristic 1 Silicon dioxide (Sio 2 ) plus aluminium oxide ( Al 2 O 3 ), plus Iron Oxide ( Fe 2 O 3 ), Percent by mass min. 2 Silicon dioxide ( SiO 2 ), Percent by mass, min 3 *Reactive silica in percent by mass, min 4 Magnesium oxide ( MgO), percent by mass, max 5 Total Sulphur as Sulphur trioxide (SO 3 ). Percent by mass, max 6 Available alkalis as sodium oxide (Na 2 O) in percent by Table-1 Chemical and Physical Properties of Flyash Result obtained in % Requirement as Part Siliceous Calcareous Pulverized Pulverized Fuel Ash Fuel Ash Method of Test Ref. Annex mass, Max 7 Total chlorides in percent by mass Max B B No / NCB 8 Loss on ignition, in percent by mass,max Calcium Oxide Moisture content Physical Properties Sr.No. Name Of The Tests 01 Fineness - Specific Surface in m2/kg Lime Reactivity, N/mm Compressive Strength, N/mm Drying Shrinkage Soundness, 0.33 Observations 1727

4 Figure: 1 SEM view of Flyash Table 2: Test Results of Polyester fibers. Product Name Product Code CTP 2024 / CTP 2424 Application Concrete Indian Roads Congress Accredited Material Polyester Denier (Approximate) 11.7 Shape(Cross-section) Triangular Trilobal Cut Length 12.1 mm Diameter 30-35u Specific Gravity 0.91 Packing Type Pouch Dispersion Excellent Melt Point Elastic Modulus, psi (ACI) Recron 3s Polyester 12mm Triangular Conforming to type III fibers under ASTM C:1116 ph 7.3 ± 10% Colour Colourless & White Solubility in Water Not Soluble in Water Water Absorption (% by Wt.) Nil Alkaline Resistance Conforms to Test Procedure laid by ICBO AC 32 UV Stability Higher UV Resistance

5 Figure 2: SEM View of Polyester Fibre 3.0 Experimental Set up Based on the trial mix for different proportion of ingredients the final design mix were prepared for all the selected mix and proportion of fly ash 50, 55 and 60 %. Latter in second stage with the same proportion 0.25% and 0.50% of polyester fibre were added. For each batching of the sample and design mix the slump values were measured after 60 min retention period using standard slump cone and results were confirmed as per B: For compression strength standard 150mm cube were casted to measure strength at 3, 7, 28 and 56 days. Sample were casted and tested as per B 516 Comparative study was made for strength development for different dose of flyash as well as with different inclusion of 12mm triangular shaped polyester fibre content i.e and 0.50%

6 M25 SAM PLE Journal of Engineering Research and Studies Table 3. HVFA Design Mix. C FA C+FA W SP W/C +FA SA ND C A <20M M C A <10M SLUMP MM DENSIT Y KG/M3 A A A M30 SAMPLE C FA C+FA W SP W/C+FA SAND C A <20MM C A <10M SLUMP MM DENSITY KG/M3 B B B M35 SAMPLE C FA C+FA W SP W/C+FA SAND C A <20MM KG.M3 C A <10M SLUMP MM DENSITY KG/M3 C C C M40 SAMPLE C FA C+FA W SP W/C+FA SAND C A <20MM C A <10M SLUMP MM DENSITY KG/M3 D D D A: M25,B=M30,C=M35,D=M40, 1= 50 2=55 3=60 % flyash 0= no fibre 1=0.25 and 2=0.50% fibre 4.0 Results and Discussion The batching for all the designed mix and inclusion of varied flyash as well as polyester fibres have made as per the standard procedure. Slump for all the batches were measured after 60 min. retention period and tabulated in table no.4. The comparative study for different mix is shown in figure [3]. Compressive strength measurement for all the mix with 0.0 and 0.25% fibre dose was measured 3,7,28 days as shown in table no.5. The values obtained for plain HVFA concrete at 3,7,28 and 56 days are shown graphically in figure [4]. Comparison of compressive strength according to variation in fibre content 0.0 and 0.25% at end of 28 days for all mix is shown graphically in figure [5]

7 Table 4: Slump in mm. after 60 min retention. MIX Fly Ash 50% 55 % 60% Fibre 0.00% 0.25% 0.50% 0.00% 0.25% 0.50% 0.00% 0.25% 0.50% w/c S w/c S w/c S w/c S w/c S w/c S w/c S w/c S w/c S M M M M

8 Table 5. Compressive Strength N/mm2. Mix Days/ 50% flyash 55% flyash 60%flyash Fibre Figure 4. Compressive Strength Comparisons (Plain HVFA concrete).

9 Figure Days Compressive Strength Comparison, (Plain and 0.25% Fibre HVFA)

10 5.0 CONCLUSION All design mix satisfies the guide line of CANMET in terms of proportion range of the ingredients for low medium and high strength HVFA concrete. The mix found to be homogeneous and workable. Water to cementitious material ratio varies from 0.25 to 0.40 and slump at 60 min retention period varies between 85 to 100mm for different mix. Values observed satisfy the provision of B: The compressive strength gaining is comparatively slower at 3 and 7 days for all mix particularly for high 60% of flyash and higher mix M35 and M40. Targeted values at 7 days for plain HVFA concrete is of the 72% to 78% which is as better as normal concrete without flyash. Beyond 7 days the increase in strength is of order 65 to 76% and all mix shows satisfactory values at age of 28 days. Inclusion of fibre at the rate of 0.25% by mass of the cementitious material does not have much effect on the w/c ration and 60 min. slump values as well. Uniform matrix and well dispersed fibre and homogeneous mix observed with adequate workability. For higher proportion of cementing material in higher concrete grade the dosage of plasticizer was increased to 1.00% to achieve desired slump and workability. Increase in compressive strength at 7 days age for all mix varies between 7.00 to 9.50% Increase in 28 days compressive strength as compared to plain HVFA concrete is of the order 9.75 to 15 % With considerable reduction in cost of cementing material and including marginal proportion of polyester fibre strong and durable eco friendly concrete can be produced and applied in the construction sectors like pavement, foundations, mass concrete and gravity structures.

11 6.0 REFERENCES 6.1 Journal & Proceedings: 1. Bouzoubaa,N.,Fournier,B.,Malhotra,V.M.,and D.M.Golden, Mechanical Properties and Durability of Concrete Made with HVFA Blended Cements Produced in a Cement Plant ;CANMET Report MTL (J),October 2001, Natural Resources Canada, Ottawa, Canada. 2. Bouzoubaa, N., Zhang, M.H. and Malhotra V.M., Mechanical Properties and Durability of Concrete made with High-Volume Fly Ash Blended Cement Using a Coarse Fly Ash, Cement and Concrete Research, Vol.31, No. 3, October,2001,pp Desai, J.P., Construction and Performance of High Volume Fly Ash Concrete Roads in India, ACI SP-221, V.M.Malhotra, ed., 2004,pp Malhotra, V.M., Making Concrete Greener with Fly Ash ; Concrete International, V.21, No.5, May 1999, pp Malhotra, V.M., CANMET Investigations Dealing with High- Volume Fly Ash Concrete ; CANMET Publication: Advance in Concrete Technology, MSL 92-6, 1992, pp Malhotra, V.M, High-Performance, High-Volume Fly Ash Concrete: A Solution to the Infrastructure Needs of India ; Indian Concrete Journal, Mumbai, India, February Malhotra, V.M., and Mehta, P.K.., Pozzolanic and Cementitious Materials ; Gordon and Breech Publishers, 1996,191 pp. 8. Mehta, P.K., Reducing the Environmental Impact of Concrete. Concrete International, V.23. No.10, Oct Mehta P.K.and V.M.Malhotra, High Performance, High-Volume Fly Ash Concrete, February 2002, pp.15-32, pp.34-36, pp , pp.43-49, pp Mehta P.K., Concrete Technology for Sustainable Development, Concrete International, V.21, No.11, Nov M.S.Shetty, Concrete Technology Theory and Practice, Pub. S. Chand, 2006, pp , pp Naik, Tarun et al, Mechanical Properties and Durability of Concrete Pavements Containing High Volumes of Fly Ash; ACI SP-212, June 2003, V.M.Malhotra ed., pp National Codes: Indian standard code of practice for plain and reinforced concrete for general building construction, 456:2000. Bureau of Indian Standards, New Delhi. Method of test for strength of concrete, 516:2000, Jan-99. B, New Delhi. Specification for fly ash for use as pozzolana and admixture (first revision), 3812:1981, B, New Delhi. Recommended guidelines for concrete mix design, 10262:1982, Jan-99.B, New Delhi. Specification for 53 grade ordinary Portland cement, 12269:1987, Jan- 99.B, New Delhi. Chemical & Physical Requirements for Fly Ash for Use with Portland cement Concrete C 618 American Society For Testing Of Material