7.24 Three concrete mixes with the same ingredients, except the amount of mix- ing water, and their slump values were ob

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7 24 Three Concrete Mixes With The Same Ingredients Except The Amount Of Mix Ing Water And Their Slump Values Were Ob 1 (73.71 KiB) Viewed 79 times

7.24 Three concrete mixes with the same ingredients, except the amount of mix- ing water, and their slump values were obtained. Three 100 mm x 200 mm concrete cylinders were prepared for each mix. The cylinders were cured for 7 days and then tested for compressive strength. The test results are as shown in Table P7.24. Assume that the aggregate was at the saturated surface-dry condition before adding mixing water. It is required to do the following: a. Plot the relationship between slump and amount of mixing water for all mixes. Comment on the effect of increasing the amount of water on workability b. Determine the compressive strength of each cylinder after 7 daye. c. Determine the average compressive strength of each mix after 7 days. d. Using Figure 7.24, estimate the compressive strength after 28 days (f) for each mix. e. Determine the w/c ratio for each mix. Plot the average fc values versus w/c ratios for all mixes. Comment on the effect of increasing the w/c ratio on the compressive strength. Mamlouk Zaniewski, Materials for Civil and Construction Engineers, Third Edition. Copyright c 2011 Pearson Education, Inc TABLE P7.24 Estimated Averago Compres- Mass of Mass of Compressive Compressive sive Strength Cement Water Slump Cylinder Maximum Strength after Strength after after 28 Days (kg) (kg) (mm) No. Load (kN) 7 Days (MPa) 7 Days (MPa) (MPa) Mix No. 1 1 10 5 40 2 3 1 138.2 175.9 136.9 100.7 115.2 113.6 73.3 2 10 5.5 55 2 3 1 3 10 6 75 2 انا | نما 78.4 76.0 3 Assume that the water listed here is above the saturated surface-dry (SSD) condition of the aggregate.