CIVL 1112 - Assignment #5

 Name: ____________________________________

 

"Sixty years ago I knew everything; now I know nothing; education is a progressive discovery of our own ignorance." 
Will Durant

Objective

The purpose of this assignment is twofold: (1) use the ACI concrete mix design procedure; and (2) to continue to develop your spreadsheet skills. 

Part 1: Use the ACI method for concrete mix design to proportion a 1 yd3 of concrete. Compute the weight of each mix component by hand to meet the follow specifications:

The concrete is required for an interior column. The 28-day compressive strength should be 4,000 psi. The slump should be between 3 and 4 inches and the maximum aggregate size should not exceed 1 inch. The properties of the materials are as follows:

  • Cement : Type I, specific gravity = 3.15
  • Coarse Aggregate: Bulk specific gravity (SSD) = 2.72;
    absorption capacity = 1.3%;
    dry-rodded unit weight = 103 lb/ft3;
    surface moisture = 1%
  • Fine Aggregate: Bulk specific gravity (SSD) = 2.67;
    absorption capacity = 1.5%;
    fineness modulus = 2.70
    surface moisture = 2%

Follow the homework format given in class and report the weigh of cement, water, coarse aggregate, and fine aggregate required per cubic yard for this application.  If we were to mix this concrete in the lab using the yellow mixer (about 1 cubic foot in volume), what would be the required weigh of cement, water, coarse aggregate, and fine aggregate?

Part 2: Develop a Excel spreadsheet that computes the amount of fine aggregate using the ACI Mix Design volume method, given the amounts of water, cement, and coarse aggregate and then adjusts each mix component for moisture content. 

The concrete is required for an interior column. The 28-day compressive strength should be 5,000 psi. The slump should be between 1 and 2 inches and the maximum aggregate size should not exceed ¾ inch. The properties of the materials are as follows:

  • Cement : Type I, specific gravity = 3.15
  • Coarse Aggregate: Bulk specific gravity (SSD) = 2.70;
    absorption capacity = 0.5%;
    dry-rodded unit weight = 96 lb/ft3;
    surface moisture = 1%
  • Fine Aggregate: Bulk specific gravity (SSD) = 2.67;
    absorption capacity = 1.1%;
    fineness modulus = 2.70
    surface moisture = 1.5%

In the Volume Calculation section, round all of your results to two decimal places. The final component weights, in both the Volume Calculation and Moisture Adjustment sections, should be rounded to the nearest integer. The calculations shown in the spreadsheet below are the same as an example problem in the ACI Mix Design notes.

Part 3. Read the Chapters 9 and 10 in the "A Mind for Numbers" by Barbara Oakley.