Aci Mix Design Method Example

Transcript

EA102 American Concrete Association (ACI) Absolute Volume Method of Concrete Mix Design EXAMPLE ACI MIX DESIGN Mix Component Properties: Type: 10 Specific Gravity: 3.155 Cement  Coarse Aggregate  Fine Aggregate  Nominal Maximum Particle Size: SSD Bulk Specific Gravity: % Absorption Capacity: Dry-Rodded Density: 10 mm 2.660 3.50% 1.530 Mg/m3 SSD Bulk Specific Gravity: 2.700 % Absorption Capacity: 1.50% Fineness Modulus: 2.700 Desired Mix Properties: A 30 kg batch on non-air-entrained concrete with a slump in the 80 to 100 mm range and a water/cement ratio of 0.5 is required. SOLUTION: 1. Determine densities of all materials to be used: Specific Material Gravity Water 1.0 Cement 3.155 SSD Fine Aggregate 2.700 SSD Coarse Aggregate 2.660 Dry-Rodded Coarse Aggregate 2. ρ = G x ρw x ρw = Density (kg/m3) x 1000 = x 1000 = x 1000 = x 1000 = 1000 3155 2700 2660 1530 Mass of mixing water in water in 1 m3 of mix = 228 kg = 0.228 m3 (Table 4a for non-air-entrained, non-air-entrained, Nominal Maximum size = 10mm and slump between 80 & 100 mm) 3. Volume of air in air in 1 m3 of mix is 3.00% of 1 m 3 or 0.030 m3 (Table 4c for non-air-entrained, Nominal Maximum size = 10mm) 1 4. If w c  0.5, then c  w 0.5 The volume of cement 228 kg 456 kg  The mass of cement required = 456 kg 0.5 456 kg The volume of cement required = 0.145 m3 3 3155 kg/m    5. Volume of dry-rodded coarse aggregate = 0.47 m3 (Table 3 for Nominal Maximum size = 10 mm and fineness modulus of 2.70) 6. SSD mass of coarse aggregate = 0.47 m3 x 1530 kg/m3 = 719 kg SSD volume of coarse aggregate  719 kg 2660 kg/m 3 = 0.270 m3 7. Sum of known volumes = (0.228 + 0.030 + 0.145 + 0.270) m 3 = 0.673 m3 SSD volume of fine aggregate = 1 – 0.673 m3 = 0.327 m3 SSD mass of fine aggregate = 0.327 m3 x 2700 kg/m3 = 883 kg 8. Total mass of 1 m3 of mix = (228 + 456 + 719 + 883) kg = 2286 kg/m3 The proportioning factor  2286 kg 30 kg = 76.2 Each mass for the 1 m3 of mix is then divided by this factor: Materials Cement Water Coarse Aggregate Fine Aggregate Air Totals Mass (kg/m3) 456 228 719 883 Volume (m3) 0.145 0.228 0.270 0.327 0.030 1.000 2286 SSD Mix Masses (kg) 5.984 2.992 9.436 11.588 30.000 NOTE: The information in this table should appear in the table on Datasheet 7.5. Do not present it twice! 2