CMT-Activity No. 8-Rosaros.pdf

27 de May de 2023
1 de 2

CMT-Activity No. 8-Rosaros.pdf

• 1. 72 Name: ROSAROS, KENT ARNEL T. Student Number: 20180125966 Activity No. 8 Unit Weight, Yield, and Air Content (Gravimetric) of Concrete Reference: AASHTO T 121-97, ASTM C 138-92 Objective: To determine the unit weight, yield and air content of freshly mixed concrete. Data/Calculation: Calculate the unit weight of concrete, W, by dividing the net weight by the volume of the measure used. Calculate the yields as follows: W W m Y l = ) ( 3 (19-1) Calculate the air content as follows:   units) (SI 100 ) ( x Y V Y A − = (19-2) Where: W = unit weight of concrete, kg/m3 V = total absolute volume of the component ingredients in the batch, m3 Wl = total weight of all materials batched, kg Y = volume of concrete produced per batch, m3
• 2. 73 Computation: Empty mass of container, kg 3.55 Mass of container with concrete, kg 20.49 Volume of container, m3 0.0071 Density, kg/m3 2385.915 Unit weight, kN/m3 23.406 Total batch weights, kg 2,384 Yield, m3 1 Discussion/Conclusion: Mass of concrete = Mass of container with concrete – Empty mass of container Mass of concrete = 20.49 – 3.55 = 16.94 kg Density = Mass / Volume of Container = 16.94 kg / 0.0071 m3 = 2385.915 kg/m3 Unit Weight (kN/m3 ) = Density x Acceleration due to Gravity x 1/1000 Unit Weight (kN/m3 ) = 2385.915 kg/m3 x 9.81m/s2 x 1/1000 = 23.406 kN/m3 Yield = Total weight of all materials batched / unit weight of concrete Yield = 2384 kg / 2385.915 kg/m3 = 0.999 m3 ≈ 1 m Air content = [(yield – volume)/yield] x 100 Ari content = [(1-0.0071)/1] x 100 = 99.29