Increasing the amount of sand in a concrete usually decreases the amount of water needed to make the concrete workable. OAI True O B) False This non-destructive test method is typically used to isolate zones of poor-quality concrete prior to coring: OA Rebound hammer test O B) GPR O Penetration resistance O DI Pull-out test The density of a concrete column is 2380 kg/m^3 and the height of the column is 3.8 m. If the column is circular with a diameter of 250 mm, calculate the dead load of the column in kN. OA) 444 O B) 4.36 O9 4355 OD) 44.4

The increased surface area of manufactured aggregates (e.g. crushed stone) contributes to a more fluid and flowable concrete in its fresh state.  True False

Although the constituents of concrete (aggregate and hydrated cement paste) behave in a linear elastic manner if stress is applied to them and the resulting strain is measured, concrete is not a linear elastic material throughout its entire stress-strain curve.  What is the main reason for the deviation from this behavior? Interfacial transition zone (ITZ) Incomplete hydration of cementitious phases The loading rate applied according to ASTM C 39 presence of C-S-H very close to the aggregate/paste interface

1.40 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.