Project on Concrete Mix Design for various grades of Concrete

                                                                                                                              MIX DESIGN PROJECT

                                           

                                                                                                   TITLE: MIX DESIGN FOR M35 GRADE CONCRETE WITH FLY ASH. 

	TABLE OF CONTENTS
1.	AIM
2.	INTRODUCTION
3.	PROCEDURE
4.	RESULT

AIM: 

          Calculation of mix design for M35 grade concrete using fly ash as part of replacement of OPC. 

INTRODUCTION: 

             Concrete is a very complex material, its properties as well as hardened concrete is a function of right mix of constituents of concrete, which if not done properly will adversely affect the properties of concrete. Concrete mix design is a scientific and systematic process of choosing economically relative proportion of various ingredients from available material that gives cohesive concrete of desired work ability in fresh stage and desired strength and durability in hardened concrete. The process of selecting suitable ingredients for producing concrete of required strength, durability and workability as economical as possible is known as concrete mix design. 

  The compressive strength of concrete depends the quality and quantity of cement, water and aggregates. It also depends the mixing, batching, placing, compaction and curing. The selection of proper concrete ingredients is also important where concrete is being pumped in the site. Segregation and bleeding of concrete is also interlinked with the concrete mix design. 

Properties of good concrete mix: 

• It should meet the strength requirement of the structure, which is measured in the compressive strength.  
• Fulfill the durability requirement  
• It should be mixed, compacted and transported easily 
• It should be economical.  

It is therefore good concrete which saves your money and ultimately saves your life. 

FLY ASH: 

            Fly ash is a heterogenous byproduct material produced in the combustion process of coal used in power stations. As fly ash contains pozzolanic material components which react with lime to form cementitious materials. Thus, it is used in concrete, mines and dams. 

Mechanism of Fly ash: 

            If we have Portland cement and the fly ash is the pozzolana it can be represented by silica because non crystalline silica glass is the principle constituent of fly ash. It forms a calcium silicate hydrate which is a binder and fills up the space and gives us impermeability and more and more strength. 

PROCEDURE: 

 Mix proportioning of concrete using fly ash as part of replacement of OPC. 

        For the given grade of concrete, some datas are assumed as per our requirements following the specific IS codal provisions. 

Stipulations for proportioning: 

• Grade designation: M35 
• Exposure condition: Severe (Reinforced concrete) 
• Type of cement: OPC 33 grade conforming to IS 8112 
• Type of mineral admixture: Fly ash conforming to IS 3812 (part 1) 
• Maximum nominal size of aggregate: 20mm 
• Minimum cement content: 320 kg/m^3 (From table 5 of IS 456:2000- Exposure condition) 
• Maximum water cement ratio: 0.45 (From table 5 of IS 456:2000- Exposure condition) 
• Workability: 75mm 
• Method of concrete placing: Normal pouring of concrete. 
• Degree of supervision: Good 
• Chemical admixture: No admixtures used. 

Test data for materials: 

• Cement used: OPC 43 grade confirming to IS 8112 
• Specific gravity of cement: 3.15 
• Fly ash: confirming to IS 3812 (part 1)  
• Specific gravity of fly ash: 2.2 
• Specific gravity of aggregates  

                    Coarse aggregate = 2.74  

                     Fine aggregate    = 2.74 

• Water absorption: 

                    Coarse aggregate = 0.5% 

                     fine aggregate     = 1.0% 

• free surface moisture: 

                    Coarse aggregate = nil 

                    Fine aggregate     = nil. 

• Sieve analysis: 

                    Coarse aggregate: The values of course aggregate should conform to Table 2 of IS 383. 

                     Fine aggregate    : The values of fine aggregate should conform to grading zone 1 of Table 4 of IS 383. 

Target strength for Mix proportioning: 

                        Ft = Fck + 1.65 S 

                Where, 

                        Ft = Target average compressive strength at 28 days 

                        Fck = Characteristic compressive strength at 28 days 

                         S = Standard deviation.  

               Therefore, 

                         Ft = 35 + 1.65 (5) [ standard deviation taken from table 1 of  

                                                           IS 10262:2009]. 

                         Ft = 43.25 N/mm^2. 

Water cement ratio: 

        From table 5 of IS 456-2000, 

     The maximum water cement ratio for severe exposure is 0.45. Based on experience we take water cement ratio as 0.40.  

     Therefore,   

                            0.40 < 0.45, Hence OK. 

Maximum water content: 

          From Table:2 of IS 10262:2009,  

          The maximum water content for 25mm to 50mm slump having 20mm nominal size of aggregates = 186 litres. 

          For additional slump, 3% should be added for every 25mm slump. 

          Therefore, water content for 75mm slump = 186 + 3% (186) 

                                                                              = 186 + (3/100 x 186) 

                                                                              = 191.58  

                                                                              = 191 litres. 

Maximum cement content: 

          The water-cement ratio is taken as 0.40. 

          From, 

                  W/C = 0.40 

                      C = W/0.40 

                      C = 191/0.40 

                      C = 477 kg/m^3.   

 Therefore, 

            Maximum cementitious content (cement + fly ash) = 477 kg/m^3. 

From table 5 of IS 456:2000, the minimum cement content for severe condition is 320 kg/m^3. 

            Here, 

                       477 kg/m^3 > 320 kg/m^3, Hence OK. 

Fly ash addition to cement: 

• The percentage of fly ash addition needs to be decided based on project requirements and quality of materials. 
• Increase in cementitious material content and its percentage may be based on experience and trial  
• In this mix design, it is increased by 10%. 

                        cementitious material content    = 477 x 10% 

                                                                       = 524.7 kg/m^3. 

                                                  water content = 191 litres. 

                                      so, water cement ratio = 191/524.7 

                                                                       = 0.36 

         fly ash @ 30% total cementitious material = 524.7 x 30% 

                                                                       = 157.41 kg/m^3. 

                                                  cement (OPC) = 524.7 - 157.41 

                                                                       = 367 kg/m^3 

                  saving of cement while using Fly ash = 477 – 367 

                                                                        = 110 kg/m^3. 

                                         Fly ash being utilized = 157 kg/m^3.             

Volume of aggregates: 

Volume of coarse aggregate, 

           From Table 3 of IS 10262:2019, volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate (zone 1) = 0.6, (For 0.5 w/c ratio) 

           (Note: For every 0.05 decrease in water cement ratio, the volume of coarse aggregate increases by 0.01) 

            Required water cement ratio = 0.40 

            Therefore, in our case the w/c ratio is 0.10 lower when compared to 0.50 from the table 3 of IS 10262:2019. 

                          Increase in volume of coarse aggregates = 0.60 + [ (0.10 x 0.01)/0.05 ]. 

                                                                                     = 0.60 + 0.02 

                                                                                     = 0.62. 

                                            Volume of fine aggregate     = 1-0.62 

                                                                                     = 0.38. 

Mix calculations: 

  The mix calculation per unit volume of concrete shall be as follows: 

• A) Volume of concrete = 1 m^ 3  

• B) Volume of cement = Mass of cement/Sp. Gravity of cement x 1/1000. 

                                       = 367/3.15 x 1/1000 

                                       = 0.116 m^3 

• C) Volume of fly ash = Mass of fly ash/Sp. Gravity of fly ash x 1/1000. 

                                      = 157/2.2 x 1/1000 

                                      = 0.071 m^3. 

• D) Volume of water    = Mass of water/Sp. Gravity of water x 1/1000. 

                                        = 191/1 x 1/1000 

                                        = 0.191 m^3. 

• E) Volume of aggregates (FA & CA) = [ A - ( B+C+D) ] 

                                                            = [ 1 - ( 0.116 + 0.071 + 0.191 ) ] 

                                                            = 0.622 m^3. 

• F) Mass of coarse aggregate           = E x Volume of coarse aggregate  

                                                                x Sp. Gravity of coarse aggregate x 1000. 

                                                            = 0.622 x 0.62 x 2.74 x 1000 

                                                            = 1057 kg/m^3. 

• E) Mass of fine aggregate               = E x Volume of fine aggregate 

                                                               x Sp. Gravity of fine aggregate x 1000. 

                                                            = 0.622 x 0.38 x 2.74 x 1000 

                                                            = 647 kg/m^3. 

Result: 

     Required Mix proportions: 

• Cement                                  = 367 kg/m^3 
• Fly ash                                   = 157 kg/m^3 
• Water                                     = 191 litres 
• Fine aggregate                        = 647 kg/m^3 
• Coarse aggregate                    = 1057 kg/m^3 
• Water cement ratio                  = 0.36 
• Trail mix ratio                       = 1 : 1.23 : 2.02 

 Therefore, 

          These are the obtained quantity of materials and one of the trial design mix ratio required for M35 grade of concrete with fly ash addition which is assumed to be exposed to severe environmental conditions. 

                                                                                                TITLE: MIX DESIGN FOR M50 GRADE CONCRETE WITHOUT FLY ASH. 

	TABLE OF CONTENTS
1.	AIM
2.	INTRODUCTION
3.	PROCEDURE
4.	RESULT

AIM: 

          Calculation of mix design for M50 grade concrete using OPC. 

INTRODUCTION: 

             Concrete is a very complex material, its properties as well as hardened concrete is a function of right mix of constituents of concrete, which if not done properly will adversely affect the properties of concrete. Concrete mix design is a scientific and systematic process of choosing economically relative proportion of various ingredients from available material that gives cohesive concrete of desired work ability in fresh stage and desired strength and durability in hardened concrete. The process of selecting suitable ingredients for producing concrete of required strength, durability and workability as economical as possible is known as concrete mix design. 

  The compressive strength of concrete depends the quality and quantity of cement, water and aggregates. It also depends the mixing, batching, placing, compaction and curing. The selection of proper concrete ingredients is also important where concrete is being pumped in the site. Segregation and bleeding of concrete is also interlinked with the concrete mix design. 

Properties of good concrete mix: 

• It should meet the strength requirement of the structure, which is measured in the compressive strength.  
• Fulfill the durability requirement  
• It should be mixed, compacted and transported easily 
• It should be economical.  

It is therefore good concrete which saves your money and ultimately saves your life. 

PROCEDURE: 

 Mix proportioning of concrete. 

        For the given grade of concrete, some datas are assumed as per our requirements following the specific IS codal provisions. 

Stipulations for proportioning: 

• Grade designation: M50 
• Exposure condition: Extreme (Reinforced concrete) 
• Type of cement: OPC 53 grade conforming to IS 8112  
• Maximum nominal size of aggregate: 20mm 
• Minimum cement content: 360 kg/m^3 (From table 5 of IS 456:2000- Exposure condition) 
• Maximum water cement ratio: 0.40 (From table 5 of IS 456:2000- Exposure condition) 
• Workability: 40mm (Slump cone)
• Method of concrete placing: Normal pouring of concrete. 
• Degree of supervision: Good 
• Chemical admixture: superplasticizer conforming to IS 9103.

Test data for materials: 

• Cement used: OPC 53 grade confirming to IS 8112 
• Specific gravity of cement: 3.15  
• Specific gravity of aggregates  

                    Coarse aggregate = 2.74  

                     Fine aggregate    = 2.74 

• Water absorption: 

                    Coarse aggregate = 0.5% 

                     fine aggregate     = 1.0% 

• free surface moisture: 

                    Coarse aggregate = nil 

                    Fine aggregate     = nil. 

• Sieve analysis: 

                    Coarse aggregate: The values of course aggregate should conform to Table 2 of IS 383. 

                     Fine aggregate    : The values of fine aggregate should conform to grading zone 1 of Table 4 of IS 383. 

Target strength for Mix proportioning: 

                        Ft = Fck + 1.65 S 

                Where, 

                        Ft = Target average compressive strength at 28 days 

                        Fck = Characteristic compressive strength at 28 days 

                         S = Standard deviation.  

               Therefore, 

                         Ft = 50 + 1.65 (5) [ standard deviation taken from table 1 of  

                                                           IS 10262:2009]. 

                         Ft = 58.25 N/mm^2. 

Water cement ratio: 

        From table 5 of IS 456-2000, 

     The maximum water cement ratio for extreme exposure is 0.40. Based on experience we take water cement ratio as 0.32.  

     Therefore,   

                            0.32 < 0.40, Hence OK. 

Maximum water content: 

          From Table:2 of IS 10262:2009,  

          The maximum water content for 25mm to 50mm slump having 20mm nominal size of aggregates = 186 litres. 

          For additional slump, 3% should be added for every 25mm slump. 

          Therefore, water content for 40mm slump = 186. 

          As super plasticizer is used, water content can be reduced upto 29% based on previous usage results.

          Therefore, water content = 186 x 0.71

                                               = 132 litres.

Maximum cement content: 

          The water-cement ratio is taken as 0.32. 

          From, 

                  W/C = 0.32 

                      C = W/0.32 

                      C = 132/0.32 

                      C = 412.5 kg/m^3.   

 Therefore, 

            Maximum cement content  = 412.5 kg/m^3. 

            From table 5 of IS 456:2000, the minimum cement content for extreme condition is 360 kg/m^3. 

            Here, 

                       412.5 kg/m^3 > 360 kg/m^3, Hence OK. 

Volume of aggregates: 

     Volume of coarse aggregate, 

           From Table 3 of IS 10262:2019, volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate (zone 1) = 0.6, (For 0.50 w/c ratio) 

           (Note: For every 0.05 decrease in water cement ratio, the volume of coarse aggregate increases by 0.01) 

            Required water cement ratio = 0.32 

            Therefore, in our case the w/c ratio is 0.18 lower when compared to 0.50 from the table 3 of IS 10262:2019. 

                          Increase in volume of coarse aggregates = 0.60 + [ (0.18 x 0.01)/0.05 ]. 

                                                                                     = 0.60 + 0.036 

                                                                                     = 0.636. 

                                            Volume of fine aggregate     = 1-0.636

                                                                                     = 0.364. 

Mix calculations: 

  The mix calculation per unit volume of concrete shall be as follows: 

• A) Volume of concrete = 1 m^ 3  

• B) Volume of cement = Mass of cement/Sp. Gravity of cement x 1/1000. 

                                       = 412.5/3.15 x 1/1000 

                                       = 0.131 m^3  

• C) Volume of water    = Mass of water/Sp. Gravity of water x 1/1000. 

                                        = 132/1 x 1/1000 

                                        = 0.132 m^3. 

• D) Volume of chemical admixture   =  Mass of chemical admixture/Sp. Gravity of admixture x 1/1000

                                                           =  7.6/1.145 x 1/1000

                                                           =  0.006 m^3

• E) Volume of aggregates (FA & CA) = [ A - ( B+C+D) ] 

                                                            = [ 1 - ( 0.131 + 0.132 + 0.006 ) ] 

                                                            = 0.731 m^3. 

• F) Mass of coarse aggregate           = E x Volume of coarse aggregate  

                                                                x Sp. Gravity of coarse aggregate x 1000. 

                                                            = 0.731 x 0.636 x 2.74 x 1000 

                                                            = 1274 kg/m^3. 

• E) Mass of fine aggregate               = E x Volume of fine aggregate 

                                                               x Sp. Gravity of fine aggregate x 1000. 

                                                            = 0.731 x 0.364 x 2.74 x 1000 

                                                            = 729 kg/m^3. 

Result: 

     Required Mix proportions: 

• Cement                                  = 412.5 kg/m^3  
• Water                                     = 132 litres 
• Fine aggregate                        = 729 kg/m^3 
• Coarse aggregate                    = 1274 kg/m^3 
• Water cement ratio                  = 0.32 
• Trail mix ratio                       = 1 : 1.77 : 3.09 

 Therefore, 

          These are the obtained quantity of materials and one of the trial design mix ratio required for M50 grade of concrete which is assumed to be exposed to extreme environmental conditions.