Write up: Report pressure-meter content (to 0.1%), slump (nearest 1/4″ and nearest 5 mm), temperature in degrees C and F, and unit weight (in pcf and kg/m3).
PCC-Part A Plastic PCC Testing & Specimen Casting
Objective: To prepare test specimens of a pre-designed PCC mix and conduct plastic PCC tests.
Reference: ASTM C31, C173, C231, C143, C192, C138
Apparatus: Balance, accuracy to 0.01 lbs.
Large square mixing pan and trowels
Cylindrical molds
Concrete thermometer
Slump-test cone
Air pressure meter
Ruler scaled in inches
Procedure:
1. Assemble the molds.
2. Add the coarse aggregate and approximately 25% of water to the mixer. Then turn the mixer on and add the fine aggregate, cement and remaining water. Any admixture should be dispersed in the mixing water previous to mixing. Mix 3 minutes after adding the final mix water, rest 3 minutes and then mix 2 additional minutes. Discharge the mixer into a large, pre-moistened mixing pan and blend with the trowels. Be sure to get all of the mortar out of the mixer.
3. Conduct an air content and unit weight test. Measure the concrete’s slump and temperature as demonstrated on the ACI video tape.
4. Cast the strength specimens. Use the appropriate rod (small for the 4×8″ cylinders, large for 6×12″). Two layers for 4×8 and 3 layers for 6 x 12.
5. Strike off the top of the mold with the straight edge or tamping rod (do not over-finish, this creates a weakened high w/c surface layer). Mark your molds so you can identify your specimens. Put plastic bags on the cylinders and put them in a safe place. Return in 24 + or – 4 hours, strip the forms and place the specimens in the lime-water tank.
6. Throw the excess concrete into plastic buckets. Try to minimize the amount of aggregate and cement that must be washed off in the big basin. Clean up all tools and containers in running water before the concrete sets and put them in the oven.
Write up: Report pressure-meter content (to 0.1%), slump (nearest 1/4″ and nearest 5 mm), temperature in degrees C and F, and unit weight (in pcf and kg/m3).
volume of unit weight bucket = 0.25 ft^3
empty weight of unit bucket = 8.505 lb
full weight of unit bucket = 43.7567 lb
slump= 57/5
temp= 73 F
air= 7.4%
please answer all the question
and please i need small introduction and conclusion
