Four standard mortar cubes were made using nonpotable water available at the job site, and four others were made using potable water. The cubes were tested for compressive strength after 7 days of curing and produced the failure loads in kilograms shown in Table P6.24. Also, the Vicat test was conducted on the cement paste made with the questionable water and showed that the set time is 1_2 hour less than the set time of paste made with potable water. Based on these results, would you accept that water for mixing concrete according to ASTM standards? Explain why.
TABLE P6.24
Nonpotable Water | Potable Water |
6909 | 7773 |
6591 | 7400 |
6302 | 7599 |
7227 | 7364 |
Want to see the full answer?
Check out a sample textbook solutionChapter 6 Solutions
Materials for Civil and Construction Engineers (4th Edition)
Additional Engineering Textbook Solutions
Structural Steel Design (6th Edition)
Foundation Design: Principles and Practices (3rd Edition)
Elementary Surveying: An Introduction To Geomatics (15th Edition)
Structural Analysis (10th Edition)
Elementary Surveying (14th Edition)
- A materials engineer is working in a research project to evaluate the effect of one type of admixture on the compressive strength of concrete. He tested eight mortar cubes made with admixture and eight others without admixture after 28 days of curing. The compressive strengths of cubes in psi with and without admixture are shown in Table P6.40.Using the statistical t-test, is there a significant difference between the meansof the compressive strengths of the two cement mortars at a level of signifi-cance of 0.10?arrow_forwardIn a ready-mix plant, cylindrical samples are prepared and tested periodically to detect any mix problem and to ensure that the compressive strength is higher than the lower specification limit. The minimum target value was at 42.0 MPa. The following compressive strength data were collected: All in Mega-Pascal (MPa) 41.8, 38.3, 42.5, 39.6, 42.5, 39.3, 41.2, 40.9, 39.8, 41.6 42.9, 43.4, 39.9, 44.7, 45.1, 43.9, 42.4, 41.7, 41.1, 42.1 Calculate the Arithmetic Mean, Median, and Standard Deviation. (Non-anonymous question@) .arrow_forward2. In a ready-mix concrete plant, cylindrical samples are prepared and tested periodically to detect any mix problem and to ensure that the compressive strength is higher than the lower specification limit. The minimum target value was set at 5,000 psi. The following compressive strength data were collected. Sample No. 1 2 3 4 5 6 7 8 9 10 Compressive strength (psi) 5595 5139 6359 5192 5188 5241 5964 5875 6155 5115 Sample No. 11 12 13 14 15 16 17 18 19 20 Compressive strength (psi) 6695 5449 5278 6697 5195 6021 5320 5657 6595 5235 a. Calculate the mean, standard deviation, and the coefficient of variation of the data b. Using a spreadsheet program, create a control chart for these data showing the target value and the lower specification limit. Is the plant production meeting the specification requirement? If not, comment on possible reasons. Comment on the data scatter.arrow_forward
- 02-In the laboratory, 6 cubes (0.07 0.07 0.07) m were tested for compressive strength for ordinary portland cement. The results were recorded as shown in table below. Find the compressive strength of the sample for (3.7) day and compare with the Iraqi Specification (M.q.a No. 1984/5). Cube No. Force caused failure (KN)-3 days) Force caused failure (KN)-7 days I 2 62 64 95 97 3 69 93arrow_forward1.40 In a ready-mix plant, cylindrical samples are prepared and tested periodically to detect any mix problem and to ensure that the compressive strength is higher than the lower specification limit. The minimum target value was set at 5,000 psi. The following compressive strength data were collected. Compressive Strength (psi) Compressive Strength (psi) Sample No. Sample No. 1 5595 11 6695 2 5139 12 5449 6359 13 5278 4 5192 14 6697 5 5188 15 5195 6. 5241 16 6021 7 5964 17 5320 5875 18 5657 6155 19 6595 10 5115 20 5235 a. Calculate the mean, standard deviation, and the coefficient of variation of the data. b. Using a spreadsheet program, create a control chart for these data showing the target value and the lower specification limit. Is the plant production meeting the specification requirement? If not, comment on possible rea- sons. Comment on the data scatter.arrow_forwardA materials engineer is working in a research project to evaluate the effect of one type of admixture on the compressive strength of concrete. He tested eight mortar cubes made with admixture and eight others without admixture after 28 days of curing. The compressive strengths of cubes in MPa with and without admixture are shown in Table P6.38. Using the statistical t-test, is there a significant difference between the means of the compressive strengths of the two cement mortars at a level of signifi- cance of 0.10? TABLE P6.38 Compressive Strength, MPa Cube No. With Admixture Without Admixture 1 24.2 24.4 2 25.1 26.0 3 25.6 25.6 4 24.1 25.1 23.5 24.5 25.4 25.1 7 24.4 23.4 24.2 24.5 8.arrow_forward
- Three standard mortar cubes were made using questionable water available at the job site, and three others were made using potable water. The cubes were tested for compressive strength after 7 days of curing and produced the failure loads in kN shown in the following table: Questionable Water Potable Water 56.19 63.17 53.13 65.01 52.56 60.06 The Vicat test was conducted on the cement paste made with the questionable water and showed that the set time is 1 hour more than the set time of paste made with potable water. Based on these results, would you accept that water for mixing concrete according to ASTM standards? Explain why.arrow_forwardStudents in the materials class prepared three mortar míxes with water to cement ratios of 0.50, 0.55, and 0.60. Three 50-mm mortar cubes were pre- pared for each mix. The cubes were cured for 7 days and then tested for com- pressive strength. The test results were as shown in Table P6.16. ТАBLE P6.16 Mix w/c Мaximum Compressive Average Compressive Strength (MPa) No. Ratio Cube No. Load (kN) Strength (MPa) 1 79.4 1 0.50 80.1 81.9 1. 74.7 2 0.55 2 74.5 3 72.5 1. 65.8 2 69.3 3 0.60 71.2 Determine the following: a. The compressive strength of each cube. b. The average compressive strength for each mix. c. Plot the average compressive strength versus w/c ratios for all mixes. d. Comment on the effect of increasing w/c ratio on the compressive strength of the cubes.arrow_forwardThree standard mortar cubes were made using nonpotable water available at the job site, and three others were made using potable water. The cubes were tested for compressive strength after seven days of curing and produced the following failure loads in kilograms:Based on these results only, would you accept that water for mixing concrete according to ASTM standards? Why?arrow_forward
- Home The compressive strength of samples of cement can be modeled by a normal distribution with a mean, , of 6000 kg/cm² and a standard deviation, o, of 100 kg/cm². (a) What is the probability that a sample's strength is less than 6250 kg/cm²? Ans. 0.9938. (b) What is the probability that a sample's strength is between 5800 and 5900 kg/cm²? Ans. 0.1359 (c) What strength is exceeded by 95% of the samples? Ans. 5836.5arrow_forwardIf you knew that the cubic compressive strength of a certain type of concrete is 35 MPa, then calculate the resulting load during the examination, the maximum force applied by the test device)? 1- Fission tensile test 2- Fault modulus test 3- Compressive test for cylinderarrow_forwardThe characteristic compressive strength of concrete required in a project is 25 MPa and the standard deviation in the observed compressive strength expected at site is 4 MPa. The average compressive strength of cubes tested at different water-cement (w/c) ratios using the same material as is used for the project is given in the table. w/c(%) Average compressive strength of cubes (MPa) 45 35 50 25 55 20 60 15 The water-cement ratio (in percent, roundoff to the lower integer) to be used in the mix isarrow_forward
- Structural Analysis (10th Edition)Civil EngineeringISBN:9780134610672Author:Russell C. HibbelerPublisher:PEARSONPrinciples of Foundation Engineering (MindTap Cou...Civil EngineeringISBN:9781337705028Author:Braja M. Das, Nagaratnam SivakuganPublisher:Cengage Learning
- Fundamentals of Structural AnalysisCivil EngineeringISBN:9780073398006Author:Kenneth M. Leet Emeritus, Chia-Ming Uang, Joel LanningPublisher:McGraw-Hill EducationTraffic and Highway EngineeringCivil EngineeringISBN:9781305156241Author:Garber, Nicholas J.Publisher:Cengage Learning