"A temperature recorder shall record temperatures every 15 min or less and shall be accurate and readable to 1 °C. The data from the recorder shall be evaluated at a minimum of once each week. A record of this evaluation documenting the date checked, a confirmation that the data is within the required temperature range, and the name of the individual performing this evaluation shall be maintained in the laboratory (Note).
Note: This requirement may be satisfied by an initialed and dated temperature recorder chart. Brief changes in the temperature due to door openings should be ignored."

"The moulds shall be placed on a rigid horizontal surface free from vibration and other disturbances. During initial curing, the test specimens shall be stored in a controlled environment that maintains the temperature between 15 and 25 °C immediately adjacent to the specimens. The loss of moisture from the specimens shall be prevented as specified in Clause 8.7.
The records of the maximum and minimum temperature within the curing enclosure during the initial curing period shall be reported.
Notes:
1) These curing requirements necessitate an appropriate temperature- and moisture-controlled curing facility on a project site.
2) The laboratory should develop procedures to account for the acclimatization of the maximum and minimum temperature recording or indicating device within the initial curing storage environment so that very brief extremes beyond the specified range are not incurred. The procedures should take into account the size of the initial curing environment, type of insulation (if used), anticipated ambient temperature during the initial storage period, and number of test specimens in the initial curing storage environment.
3) In hot or cold weather, a temperature can be recorded by the temperature measuring device that is only indicative of the air temperature during the very brief time in which the test specimens were initially placed in the curing environment (curing box). In the event a time and temperature data recorder is used, curing temperatures may vary outside the specified range by not more than 5 °C for a period not exceeding 30 min at either extreme. The time and temperature outside the specified range should be accurately recorded and noted on the concrete strength test report."

"When sampling from a truck agitator or truck mixer, the sample shall be taken between the 10% and 90% points of the discharge.
Clause 7.2.1 shall not apply under the following conditions:
a) when it is required that concrete be tested for slump immediately prior to the addition of superplasticizer; or
b) when precast concrete is produced in a stationary precast mixer. "

"a) Obtain three grab samples of concrete for comparative purposes from widely separated portions of the batch while the mixer is being completely emptied.

b) Keep the samples separate to represent the designated portions in the batch rather than combined to form a composite sample. When sampling, discharge the concrete at the normal operating rate for the mixer being tested, while exercising care not to obstruct or retard the discharge by an incompletely opened gate or seal. Between samples, do not allow the mixer to turn in the mixing direction. Do not add water to the batch at any time after sampling has started.."

"Control moisture loss… Note 11—(1) immerse molded specimens with plastic lids in water; (2) store specimens in a container or enclosure; (3) place specimens in damp sand pits; (4) cover specimens with plastic lids; (5) place specimens inside plastic bags; or (6) cover specimens with wet fabric. NOTE 12—Water submersion may be the easiest method to keep consistent moisture and temperature conditions during initial curing."

"Maintain temperatures between 16 and 27°C [60 and 80°F], between 20 and 26°C [68 and 78°F] for higher strength concrete (>6,000 psi). Protect from direct sunlight or contact with heating devices… NOTE 9—(1) use of ventilation; (2) use of ice; (3) use of cooling devices; or (4) use of heating devices such as electrical resistance heaters or light bulbs. Other suitable methods may be used."

"Obtain from the middle of the batch… Note 3-between 10% and 90% of the batch discharge"

"two or more portions taken at regularly spaced intervals during discharge …"

"No more than 15 minutes should be allowed between collecting the first and last portions of the composite sample"

A minimum of 28 L or 1 ft³ of concrete sample should be taken if strength specimens are to be molded.

“The moulds shall be placed on a rigid horizontal surface free from vibration and other disturbances. During initial curing, the test specimens shall be stored in a controlled environment that maintains the temperature between 15 and 25 °C immediately adjacent to the specimens. The loss of moisture from the specimens shall be prevented as specified in Clause 8.7. The records of the maximum and minimum temperature within the curing enclosure during the initial curing period shall be reported.”

Making and curing concrete compression and flexural test specimens “The moulding of strength test specimens shall be completed within 20 min after sampling, including transport and remixing… Rod each of the layers with the number of strokes indicated in Table 2… The sides of the mould shall be tapped smartly 10 to 15 times with the mallet… open hand shall be used to tap light-gauge single-use moulds that are susceptible to damage if tapped with a mallet… shall be finished after consolidation, by striking off with a strike-off bar or the tamping rod where the consistency of the concrete permits or with a wood float or trowel.”

Density and yield of plastic concrete “Place the concrete in the measure in three layers of approximately equal volume… Rod each layer with 25 strokes of the tamping rod… tap the outer sides of the measure 10 or more times with a rubber mallet… Initial strike off with the strike-off bar or the tamping rod… pressing the strike-off plate on the top surface of the measure to cover about two thirds of the surface and withdraw the plate with a sawing motion… place the plate on the top of the measure to cover the original two thirds of the surface and advance it with a vertical pressure and a sawing motion… Incline the plate and perform final strokes… excess concrete shall be cleaned from the exterior of the measure…”

Air content of plastic concrete by the volumetric method “…Fill the bowl with freshly mixed concrete in two layers of equal depth… Rod each layer 25 times… After each layer is rodded, tap the outer sides of the bowl 10 or more times with a rubber mallet… strike off the excess concrete with the strike-off bar… Clamp the top section into position on the bowl, insert the funnel, and add at least 0.5 L of water followed by the selected amount of defoaming agent.…” Roll and invert per procedure, clause 9.5. “If, at any time, during the inversion and rolling procedures liquid is found to be leaking from the meter, the test is invalid and a new test shall be started…”

Air content of plastic concrete by the pressure method Follow CSA A23.2-6C procedure for Density, then: “The flange of the container and the cover are cleaned and the cover clamped in place with the operating valve closed and the petcocks open... All air above the concrete is expelled by injecting water with a syringe through one of the petcocks... air is pumped into the air chamber…then the two petcocks are closed… The main valve leading from the air chamber to the measuring bowl is then opened quickly… strike the bowl smartly with the mallet… The gauge is tapped lightly after the gauge needle has come to rest…”

Slump of concrete “The mould shall be dampened and placed on a flat, level, moist, nonabsorbent (rigid) surface not subjected to vibration… Each layer shall be rodded with 25 strokes of the tamping rod… rodded throughout their depth so that the strokes penetrate about 25 mm into the underlying layer… filling and rodding the top layer, the concrete shall be heaped above the mould before rodding begins… mould shall be lifted in approximately 5 s by a steady upward lift…”

Temperature of freshly mixed hydraulic cement concrete “…Measure the temperature of freshly mixed concrete in the transporting device, provided there is at least 75 mm of concrete cover around the temperature measuring device in all directions… ensuring that the temperature sensing portion is submerged a minimum of 75 mm into the concrete. Gently press the concrete at the surface around the temperature measuring device to close any void… Leave the temperature measuring device in the concrete for a minimum of 2 min or until the reading stabilizes…”

“The sample shall be protected from sun, wind, and other sources of rapid evaporation, and from contamination.”

“The grab samples shall be transported to the place where plastic concrete tests are to be performed or where test specimens are to be moulded. Each sample shall be remixed with a shovel only as long as required to ensure uniformity. The sample shall be obtained, transported, and remixed within 10 min. When multiple containers are used to obtain a grab sample, the samples shall be remixed into a single composite grab sample.”

Sampling plastic concrete “When sampling from a truck agitator or truck mixer, the sample shall be taken between the 10% and 90% points of the discharge… When 100 mm × 200 mm cylinders are to be cast, a minimum 20 L sample shall be obtained for moulding three specimens to determine the strength or to determine the uniformity of the mixed concrete. When 150 mm × 300 mm cylinders are to be cast, a minimum 30 L sample shall be obtained. When 150 mm × 150 mm × 535 mm beams are to be cast, a minimum 55 L sample shall be obtained for three beams. For more than three cylinders or beams, the minimum volume shall be increased, equal to the volume of the extra specimens, plus 10%. Note: Concrete may be reused from the slump test for other tests provided that it is thoroughly recombined with the whole sample..”

“Immediately after molding and finishing, the specimens shall be stored for a period up to 48 h in a temperature range from 16 to 27°C [60 to 80°F] and in an environment preventing moisture loss from the specimens… An appropriate procedure or combination of procedures shall be used.” See Note 8 referenced for more detail.

Making and Curing Concrete Test Specimens in the Field “Rod each layer uniformly… tap the outsides of the mold at least 10 times with the mallet… Use an open hand to tap molds that are susceptible to denting or other permanent distortion if tapped with a mallet.”

Density (Unit Weight), Yield, and Air Content (Gravimetric) of Concrete “Rod each layer with 25 strokes… each layer uniformly over the cross section… After each layer is rodded, tap the sides of the measure 10 to 15 times with the appropriate mallet… Strike‐off the measure to cover about two thirds of the surface and withdraw the plate with a sawing motion to finish only the area originally covered. Then place the plate… to cover the original two thirds of the surface and advance it with a vertical pressure and a sawing motion… to advance it until it slides completely off the measure. Incline the plate and perform final strokes with the edge of the plate to produce a smooth surface.”

Air Content of Freshly Mixed Concrete by the Volumetric Method “…fill the measuring bowl… in two layers of approximately equal volume… Rod each layer 25 times uniformly… After each layer is rodded, tap the sides of the measuring bowl 10 to 15 times with the mallet… Attach the top section of the measuring bowl and insert the funnel…” Add water and appropriate amount of alcohol. Roll and invert per procedure. “If at any time, during the inversion and rolling procedures liquid is found to be leaking from the meter, the test is invalid and a new test shall be started…”

Air Content of Freshly Mixed Concrete by the Pressure Method Follow ASTM C138 procedure for Unit Weight, then: “Assemble the apparatus. Close the main air valve… and open both petcocks… inject water through one petcock until water emerges from the opposite petcock. Jar the meter gently until all air is expelled from this same petcock… Close the air bleeder valve… and pump air into the air chamber until the gauge is on the initial pressure line… Close both petcocks… Open the main air valve… Tap the sides of the measuring bowl smartly with a mallet…”

Slump of Hydraulic‐Cement Concrete “Dampen the mold and place it on a rigid, flat, level, moist, nonabsorbent surface, free of vibration… Rod each layer 25 times uniformly… allow the rod to penetrate through the layer being rodded and into the layer below approximately 1 in [25 mm]… Raise the mold a distance of 12 in [300 mm] in 5 ± 2 s…”

Temperature of Freshly Mixed Hydraulic‐Cement Concrete “…the sensor of the temperature measuring device has at least 75 mm [3 in.] of cover in all directions… Position of the temperature measuring device so that the end of the temperature sensing portion is submerged a minimum of 75 mm [3 in.] into the freshly mixed concrete. Close the void left by the placement by gently pressing the concrete around the temperature measuring device at the surface… Leave the temperature measuring device in the freshly mixed concrete for at least 2 min but not more than 5 min…”

 “Start tests for slump, temperature, and air content within 5 min after obtaining the final portion of sample… Start molding specimens within 15 min after composite sample is combined. Protect the sample from the sun, wind, rapid evaporation, and from contamination.”

“the individual samples should be combined and remixed with a shovel the minimum amount needed to create a uniform composite sample”

Sampling Freshly Mixed Concrete “The elapsed time shall not exceed 15 min. between obtaining the first and final portions of the composite sample… Transport the individual samples to the place where fresh concrete tests are to be performed or where test specimens are to be molded. They shall be combined and remixed with a shovel to ensure uniformity and compliance with the maximum time limits… Start molding specimens for strength tests within 15 min after fabricating the composite sample… Make the samples to be used for strength tests a minimum of 28 L [1 ft3]… Do not obtain samples from the very first or last portions of a mixer’s continuous discharge. [Note: No sample should be taken before 10% or after 90% of the batch has been discharged.]”