CCIL Questions and Answers graded A

Between what percentages must you sample a concrete truck? - 10% and 90% What is grab sampling? - Securing at one point of the discharge as fast as possible. Tamping rod size for 100 x 200mm cylinders - 10 +/- 1mm in diameter, between 450 mm and 600 mm Minimum sample required for 150 x 300mm cylinder? - 30L How long do you have to obtain, transport and remix sample? - 10 mins Vibration Frequency of internal vibrator - 120Hz Size of internal vibrator. - 20 to40mm in diameter, minimum 50mm in length. weight of mallet. - 0.6 +- 0.3kg strike off bar size - 6mm x 25mm x 450mm Temp of water storage tanks - 23 +/- 2 Water in a storage tank must be saturated with what? - calcium hydroxide minimum moist room humidity - 95% Range of thermometer - 0 to 50 degrees How often should a temperature recorder take a reading? - 15min How often should temperature recorder be checked to make sure it'd working? - Every 6 months If difference between temp readings is greater than 1c, temp recorder shall be adjusted to within ____ of reference measuring device. - 0.5 C How long after sampling must strength test specimens be completed? (Cylinders) - 20mins How long must cylinders sit on site? - 28+/- 8h If the slump is less than 40, you must use what method of concrete consolidation? - Vibratory How much material can be above the top of a cylinder mould that is 30MpA - 3mm How many insertions per lift with a vibrator on a 100 x 200mm cylinder? - 1 What temp can labratory test specimens be stored at when curing? - 23 +/- 2 C When shall cylinders be removed from the moulds. - 20 +/- 4h While in the mould during initial curing. What temp must cylinders be stored at? - 15 and 25 C The sides of the mould should be tapped ____ times smartly with a mallet - 10 to 15 Number of rods for a 200mm cylinder - 50 How many lifts for a cylinder when using the vibration method? - 2 Samples may be transported to the laboratory after a minimum of ___ hours of curing - 20 Self consolidating concrete must be placed in how many lifts? - 1 Size of air meter bowl for aggregate under 40mm - 7L air meter measuring bowl shall be sufficiently rigid to limit expansion to ___ of scale reading at operating pressure. - 0.1%