maximum water cement ratio for m25

DETERMINATION OF DRY DENSITY OF SOILS IN PLACE (SAND REPLACEMENT METHOD), HIGHWAY ENGINEER INTERVIEW QUESTION AND ANSWER, HOW TO CONVERT 1:2:4 FROM VOLUME TO WEIGHT, COMPRESSIVE STRENGTH TEST OF CEMENT MORTAR CUBE AS PER IS 4031 PART 6. The data required for mix proportioning is as follows. Maximum Water Cement Ratio (MORT&H 1700-3 A) 0.45: 6. Adopted Water Cement Ratio: 0.5: A-5. design a concrete for strength m25 (i.e.25 ) specification of materials:- a) grade designation : m25 b) type of cement : opc 43 grade c) max nominal size of : 20mm down aggregate d) min. M25) We all know that water cement ratio will directly affect the strength of concrete. W/c ratio = 0.47 e) Estimation of air content: Table 5 Minimum Cement Content, Maximum Water-Cement Ratio for Mix design of M25 grade concrete – IS456 codebook II. The above selected water-cement ratio should be checked against limiting water–cement ratio for the requirement s of durability and the lower of the two will be adopted. Type of Cement: OPC 53 grade confirming to IS-12269-1987: 3. Maximum cement content to avoid shrinkage cracking due to the temperature cycle in mass concrete. Maximum W/C ratio =0.50: Table 5-IS456: Adopted W/C ratio =0.50: You can reduce the water-cement ratio for M25 grade concrete based on your requirements but remember that Water-cement ratio directly affects the strength of the concrete. Type of Cement: OPC 53 grade confirming to IS-12269-1987: 3. Superplasticiser used: nil: A-6. a) Cement used : Sagar 53 grade Ordinary Portland cement conforming IS 12269. c) Chemical admixture : Super Plasticizer conforming to IS 9103. Now from the curve of Compressive Strength vs Water-Cement Ratio we have to find out the required Free Water-Cement Ratio for the strength 38.25 N/mm2 from the particular curve of the grade of cement to be used, or it can also be found out from the generalized curve of BIS, and also consider the value of Maximum Free Water-Cement Ratio from the I.S. Cement Content = Water content / “w-c ratio” = (197/0.50) = 394 kgs. Water Cement Ratio means the ratio between the weight of water to the weight of cement used in concrete mix. According to the standards a maximum water/cement ratio of 0.65 is allowed. The strength of this concrete mix is determined by the proportion on which these cement, sand, stones or aggregates are mixed. USAGE AND APPLICATION OF M25 GRADE CONCRETE: Desired slump value = 50-75 mmSo modifications are required in trial mix 1 to achieve desired workability. In the past, the specifications for concrete prescribed the proportions of cement, fine, and coarse aggregates. The above calculation you can use for all Grade of Concrete but just you have to put the different Grade of concrete like M10, M 15, M20, M25 etc. Maximum water-cement ratio 6. Step 2 (Selection of Water-Cement Ratio) Choose w.c.ratio against max w.c.ratio for the requirement of durability. ⦁ Characteristic Compressive Strength needed in the field at 28 days grade designation = M 25⦁ Maximum size of aggregate = 20 mm⦁ Workability = 55-75 mm ( slump value )⦁ Degree of quality control = Good ( as per IS 456 )⦁ Exposure type = mild⦁ Cement type = Portland Slag Cement ( IS 455 )⦁ Concrete placing method = By using pump⦁ Shape of Coarse Aggregate = Angular, ⦁ Specific gravity of cement = 3.15⦁ Specific gravity of Coarse aggregate = 2.84⦁ Specific gravity of fine aggregate = 2.64⦁ Aggregates are assumed as saturated surface dry⦁ Zone 2 Fine Aggregate – IS 383, Hinsworth costant = 1.65 ( for 5% risk factor )Standard Deviattion ( S ) = 4 ( for M25 as per IS 10262-2009 )Formula for tragert strength is, As per Table 5 of IS 456Maximum water/cement ratio for Mild exposure condition = 0.55Depend on experience, sleect water-cement ratio as 0.5.0.5<0.55, ( OK ), As per IS 10262-2009Maximum water content = 186 Kg/m3 (Nominal maximum size of aggregate – 20 mm), Estimated water content = 186+ (3/100) x 186 = 191.6 kg /m3. Here standard values of different materials are assumed for the mix design of M25 grade concrete. Revised w/c ratio=00.49 water – cement ratio (w/c ratio) From figure 1 Page no 4 of IS 10262 : 2019 free water cement ratio required for the target strength of 31.60 N/mm2 is 0.49 for PPC (curve 2) which is lesser than the maximum value of 0.50 prescribed for mild exposure for reinforced concrete as per Table 5 of IS 456 :2000 hence adopt 0.49 . Workability 7. a) Grade designation : M25 RCC. The water-cement rate should get maintained between o.4 and 0.6. What is Standard MixThis is an old technique for mixing concrete in a manner like 1 cement: 2 sand : 3 aggregates by their volume. 20, Maximum water-cement ratio=0.50 Based on experience, adopt water-cement ratio as 0.43, for the target mean strength and required workability 0.43<0.50, hence O.K. For preliminary calculation, water cement ratio as given is IS-456-Table 5 (also given below) for different environmental exposure condition, may be used. Your email address will not be published. Adopted w/c Ratio = 0.38   then Cement Content = 136.80/0.38 = 360 kg/m³ ,from Table 5 of IS 456, minimum cement content for ‘moderate’ exposure conditions is 300 kg/m³  but taken  360 kg/m³ > 300 kg/m³ hence ok. As per MORT&H 5th revision for moderate exposure  with reference to Table number 1700-2  maximum water cement ratio 0.45 & minimum cement 340 kg/m³ is specified but we had taken 360 kg/m³ , hence ok, 7. It has a volumetric batching. Actual reduced volume of fine aggregate content = 1 – 0.59 = 0.41. Therefore, target strength of concrete = 25 + 1.65 x 4 = 31.6 N/mm². M7.5, M10,M15,M20,M25. 394 kg/m3 > 300 kg/m3, hence, OK. As per clause 8.2.4.2 of IS: 456. B. As we knowWater/cement ratio = 0.5Estimated water content = 191.6 kg /m3As per IS 456 Table No 5Minimum cement Content = 300 kg/m3 ( mild exposure condition )383.2 kg/m3 > 300 kg/m3, (OK)Now check for durability requiremnt from IS 456In the present scenario against mild exposure and for the case of reinforced concrete the minimum cement content is 300 kg/m3 which is less than 383.2 kg/m3.So,Cement content adopted = 383.2 kg/m3.According to IS: 456 clause 8.2.4.2Maximum cement content = 450 kg/m3. If the water/cement ratio is more than 0.5, the volume of coarse aggregate is to be reduced to enhance the fine aggregate content. From the Table 5 of IS 456 for Very severe Exposure maximum Water Cement Ratio is 0.50 0.47 < 0.50Hence ok. A-5 SELECTION OF WATER CONTENT From Table 2 of IS 10262:2009, maximum water content for 20 mm aggregate = 186 litre (for 25 to 50 mm slump range) Estimated water content for 100 mm slump = 186+ (6/186) = 197 litre. 0.44 < 0.50 < 0.45 hence ok. 6. Durability Criteria as per IS 456-2000 Exposure Plain Concrete Reinforced Concrete Min. Types of Mixes. So,Coarse aggregate as percentage of total aggregate = 0.558 – 0.01 = 0.548, W/c = 0.55Water content will be kept constant.Cement content = (197.4/0.55) = 358.9 kg/m3So, volume of all in aggregate= 1 – [{(358.9/(3.15 x 1000)} + (197.4/1000)] =0.688 m3Mass of coarse aggregate = 0.688 x 0.548 x 2.84 x 1000 = 1070.75 kg/m3Mass of fine aggregate = 0.688 x 0.452 x 2.64 x 1000 = 821 kg/m3, Cement = 358.9 kg/m3Water = 197.4 kg/m3FA = 821 kg/m3CA = 1070.75 kg/m3. The Mix Design process is normally implemented for the structure that needs higher grades of concrete like M25, M30, etc, and where consumption of Concrete is high.Concrete Mix Design for M20, M25, M30, and higher grades of concrete can be calculated from the example given below. We take 0.42 as a ratio of W/C. Refer to concrete slump test . As per Table 3 of IS 10262- 2009,Nominal maximum size of aggregate = 20 mm,Fine Aggregate = Zone IIWater/cement = 0.5Volume of coarse aggregate per unit volume of total aggregate = 0.62. Step 2 — Selection of water/cement ratio:-From Table 5 of IS 456, (page no 20) Maximum water-cement ratio for Mild exposure condition = 0.55. Able to Learn what is grade of concrete you can cot use aggregate in SSD condition -⦁ care... A general estimate of 28-day compressive strength & Around Structures cement conforming is 12269. c ) maximum nominal aggregate:... Of these parameters shall be obtained the laboratory tests as per exposure =. Slump test we can say s a design mix, both of these parameters be... This table tend to be conservative ( ACI, 2000 [ 1 ] ) the required... The exposure condition limits the minimum cement content ( MORT & H 1700-3 a 0.45... 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