Chapter 7, Problem 7.43QP

Three batches of concrete were prepared using the same materials and ingredients, except that they have water-cement ratios of 0.50, 0.55, and 0.60, respectively. The following tests were performed on specimens made of the three batches:

• Compressive strength test on 100 mm × 200 mm cylinders
• Center-point flexure test on 100 mm × 100 mm × 300 mm beams
• Split tension test on 150 mm × 300 mm cylinders

Three replicates were tested for each test. Table P7.43 shows the average failure loads for the three replicates of each case.

It is required to do the following:

1. a. Complete Table P7.43
2. b. Using an Excel sheet, plot the relationships between water-cement ratio and compressive strength, modulus of rupture, and tensile strength on the same graph. Label all axes and curves.
3. c. Comment on the effect of water–cement ratio on the compressive strength, modulus of rupture, and tensile strength.

TABLE P7.43

w/c Ratio	Compressive Strength Test		Flexure Test		Split Tension Test
	Failure load (kN)	Compressive Strength (MPa)	Failure load (kN)	Modulus of Rupture (MPa)	Failure load (kN)	Tensile Strength (MPa)
0.50	204.2		18.6		237.2
0.55	141.7		12.2		216.1
0.60	110.5		10.0		191.1