A STUDY ON HIGH PERFORMANCE CONCRETE WITH SILICA POWDER PROJECT MEMBERS: G.GURU PRASATH (91707103010) K.SELATHU RAJA (91707103043) M.SELVARAJ (91707103044) R.VISHNU RAJA (91707103054) GUIDED BY Mrs.S.KARTHIYAINI M.E., (ASSISTANT. PROFESSOR.)

OBJECTIVES TO STUDY THE COMPRESSIVE STRENGTH OF CONCRETE USING SILICA POWDER

silica powder Silica powder is the by product of silican metal or ferrosilican alloys. Silica powder is a material consist of amorphous silican dioxide

silica powder

Uses of silica powder Plastics: Most preferred mineral in PVC chappal, PVC pipes and industrial products Rubber: Widely used in high value rubber products industry. These are also used in distempers, emulsion paints, architectural finishes, flat paints traffic paints, industrial primer, undercoats, putties and finishes Paints: Versatile application in paint convenient filler in paper manufacture Used widely in construction chemical, rigid, PVC pipes, leather cloth industry, cable compound, and used for dusting, polishing, neutralizing and other processes.

MATERIALS USED Cement(43 grade) OPC. Fine aggregate confirming to zone II. Coarse aggregate of 12mm down size. Water both for mixing as well as curing. Silica powder

MIX DESIGN FOR M40 GRADE Grade M40 Designation = M-40 Type of cement = O.P.C-43 grade Brand of cement = Ultra Tech Sp. Gravity Cement = 3.15 Fine Aggregate = 2.61 Coarse Aggregate (12mm) = 2.65 Minimum Cement = 400 kg / m3 Maximum water cement ratio = 0.45 Mix Calculation Target Mean Strength = 40 + (5 X 1.65) = 48.25 Mpa 2. Selection of water cement ratio:- Assume water cement ratio = 0.4 3. Calculation of cement content: - Assume cement content 400 kg / m3 4. Calculation of water: - 400 X 0.4 = 160 kg Which is less than 186 kg (As per Table No. 4, IS: 10262) Hence o.k.

5. Calculation for C.A. & F.A.: – As per IS : 10262 , Cl. No. 3.5.1 V = [ W + (C/Sc) + (1/p) . (fa/Sfa) ] x (1/1000) V = [ W + (C/Sc) + {1/(1-p)} . (ca/Sca) ] x (1/1000) Where V = absolute volume of fresh concrete, which is equal to gross volume (m3) minus the volume of entrapped air , W = mass of water ( kg ) per m3 of concrete , C = mass of cement ( kg ) per m3 of concrete , Sc = specific gravity of cement, (p) = Ratio of fine aggregate to total aggregate by absolute volume , (fa) , (ca) = total mass of fine aggregate and coarse aggregate (kg) per m3 of Concrete respectively, and Sfa , Sca = specific gravities of saturated surface dry fine aggregate and Coarse aggregate respectively. As per Table No. 3 , IS-10262, for 20mm maximum size entrapped air is 2% . Assume F.A. by % of volume of total aggregate = 36.5 % 0.98 = [ 160 + ( 400 / 3.15 ) + ( 1 / 0.365 ) ( Fa / 2.61 )] ( 1 /1000 ) => Fa = 660.2 kg Say Fa = 660 kg. 0.98 = [ 160 + ( 400 / 3.15 ) + ( 1 / 0.635 ) ( Ca / 2.655 )] ( 1 /1000 ) => Ca = 1168.37 kg. Say Ca = 1168 kg. Hence Mix details per m3

MIX RATIO FOR M40 Cement = 400 kg Water = 160 kg Fine aggregate = 660 kg Coarse aggregate 12 mm = 514 kg Admixture = 0.6 % by weight of cement = 2.4 kg. Water: cement: F.A.: C.A. = 0.4: 1: 1.65: 2.92

EXPERIMENTAL PROCEDURE 48 cubes had been cast to study the compressive strength variations due to the addition of silica powder in three different compositions. 7days and 28days compressive strength is to be calculated. The results are to be compared to achieve a conclusion.

CONCRETE CUBES ARE PREPARED BY FOLLOWING STAGES Batching of materials Mixing Transporting Casting Curing Storage

CUBES CASTING FOR 7DAYS M40 GRADE

RESULTS OBTAINED FOR M40 GRADE MIX COMPRESSIVE STRENGTH (7 DAYS) MPa Sample1 Sample2 Sample3 Average CONTROL 29.08 27.24 28.51 28.27 SILICA POWDER 5% 28.71 28.53 27.72 28.32 SILICA POWDER 10% 26.46 25.53 25.19 25.72 SILICA POWDER 15% 24.31 25.73 23.01 24.35

CUBES CASTING FOR 28DAYS M40 GRADE

COMPRESSIVE STRENGTH (28 DAYS) MPa Compressive strength for 28 days (M40) MIX COMPRESSIVE STRENGTH (28 DAYS) MPa Sample1 Sample2 Sample3 Average CONTROL 59.78 57.70 57.45 58.31 SILICA POWDER 5% 58.26 58.93 57.41 58.20 SILICA POWDER 10% 57.92 58.16 56.28 SILICA POWDER 15% 57.38 57.85 58.49 57.90

Mix design for M50 grade Parameters Grade Designation = M-50 Type of cement = O.P.C-43 grade Brand of cement = Ultra Tech Sp. Gravity Cement = 3.15 Fine Aggregate = 2.61 Coarse Aggregate (12mm) = 2.65 Mix Calculation 1. Target Mean Strength = 50 + ( 5 X 1.65 ) = 58.25 Mpa 2. Selection of water cement ratio water cement ratio = 0.35 3. Calculation of water Approximate water content for 12mm Size of aggregate = 180 kg / m3 (As per Table No. 5 , IS : 10262 ). As plasticizer is proposed we can reduce water content by 20%. Now water content = 180 X 0.8 = 144 kg / m3 4. Calculation of cement content Water cement ratio = 0.35 Water content per cum of concrete = 144 kg Cement content = 144/0.35 = 411.4 kg / m3 Say cement content = 412 kg / m3

5. Calculation for C.A. & F.A Volume of concrete = 1 m3 Volume of cement = 412 / ( 3.15 X 1000 ) = 0.1308 m3 Volume of water = 144 / ( 1 X 1000 ) = 0.1440 m3 Total weight of other materials except coarse aggregate = 0.1308 + 0.1440 +0.0043 = 0.2791 m3 Volume of coarse and fine aggregate = 1 – 0.2791 = 0.7209 m3 Volume of F.A. = 0.7209 X 0.33 = 0.2379 m3 (Assuming 33% by volume of total aggregate ) Volume of C.A. = 0.7209 – 0.2379 = 0.4830 m3 Therefore weight of F.A. = 0.2379 X 2.61 X 1000 = 620.919 kg/ m3 Say weight of F.A. = 621 kg/ m3 Therefore weight of C.A. = 0.4830 X 2.655 X 1000 = 1282.365 kg/ m3 Say weight of C.A. = 1284 kg/ m3 Hence Mix details per m3

MIX RATIO FOR M50 GRADE Cement = 412 X 1.025 = 422 kg Water = 144 X 1.025 = 147.6 kg Fine aggregate = 621 kg Coarse aggregate 12 mm = 514 kg Water: cement: F.A.: C.A. = 0.35: 1: 1.472: 3.043 

CUBES CASTING FOR 7DAYS M50 GRADE

COMPRESSIVE STRENGTH (7 DAYS) MPa Compressive strength for 7 days (M50) MIX COMPRESSIVE STRENGTH (7 DAYS) MPa CONTROL 38.33 37.85 37.12 37.76 SILICA POWDER 5% 36.45 36.23 35.55 36.07 SILICA POWDER 10% 33.89 34.23 33.56 SILICA POWDER 15% 31.76 32.08 31.68 31.84

CUBES CASTING FOR 28DAYS M50 GRADE

COMPRESSIVE STRENGTH (28 DAYS) MPa Compressive strength for 28 days (M50) MIX COMPRESSIVE STRENGTH (28 DAYS) MPa sample1 sample2 sample3 Average CONTROL 67.28 66.76 68.54 67.52 SILICA POWDER 5% 65.19 65.83 64.38 65.13 SILICA POWDER 10% 63.82 64.71 63.18 63.90 SILICA POWDER 15% 62.25 60.73 61.62 61.53

CONCLUSION In our study we have made samples of M40 and M50 grade concrete cubes of dimension 100 mm x 100 mm x 100mm ratio of mix design were 1:1.65:2.92 and 0.35: 1: 1.472: 3.043 respectively were designed according to the IS code method. A addition of 5%, 10%, 15% of silica were added to the normal grade of concrete mix and above cubes are further cast. These cubes were tested for compression strength on 7 days and 28 days from the casting. These compressive strength of the specimen were compared with one another and final output shows that there is slight reduction in compressive strength when it is added with silica. These reduction may be due to addition of these admixtures. Hence this admixtures can be used as a replacement of Silica as a fine aggregates in the future works. These results were concluded from our study.

REFERENCE 1.High Performance Concrete Using Fumed Silica Dr. P. Jeyabalan, Assistant Professor of Civil Engineering, and B. N. Krishnaswami Faculty in Civil Engineering, National Institute of Technology, Tiruchirappalli, Tamil Nadu 2.Investigations on the tensile strength of high performance concrete incorporating silica fume Santanu Bhanja Assistant Professor of Civil Engineering, Bengal Engineering and Science University, India Bratish Sengupta Emeritus Fellow, Bengal Engineering and Science University, India 3.High-performance concrete mix for an optimum protection in acidic conditions A.K.Tamimi 4.Effects of Silica Fume, Ultrafine and Mixing Sequences on Properties of Ultra High Performance Concrete S. Shihda and M. Arafa.