Various scales & balances
Ovens and/or Hot Plates
Most of the above equipment is very durable and will serve its purpose when used with care.
The Gyratory compactors shall be calibrated in accordance with AASHTO T312 and the manufacturer’s recommendations. Documentation of this shall be maintained by the Resident Engineer. Factory calibration and maintenance will be performed under Materials Division Service Contracts every 18 months.
Materials Division should be contacted if the machine needs repairs.
(c) Air Entrainment Meter. It is the Resident Engineer's responsibility to see that the air meters are in working condition and that the calibration is verified annually by Materials Division.
Care. After determining the air content of a concrete sample, it is imperative to quickly remove the sample from the air meter. The measuring column, bowl, cover, and all tools should be thoroughly flushed with water to remove any concrete. Equipment should be dried and stored in the air meter box.
Should an air meter need repair or replacement parts, the entire unit
should be returned to the Materials Division for this service.
The air meter shall be calibrated by the Resident Engineer in
accordance with the procedures and at the frequency outlined in the Quality Manual.
(d) Rolling Straightedge.
It is the Resident Engineer's responsibility to see
that rolling straightedges are in working condition and that the calibration is verified
annually by Materials Division personnel.
Rolling straightedges should be secured to the truck while transporting them. Their accuracy should be checked daily, and whenever error is suspected, by using shim plates available from Materials Division. Resident Engineer personnel should not adjust the rolling straightedge. Materials Division personnel must do this.
RE personnel should use a conventional 10’ straightedge to verify the areas found by the rolling straightedge if there is any question regarding the reliability of the rolling straightedge. Materials Division should be contacted to repair and/or recalibrate the rolling straightedge if the two straightedges do not correlate.
(e) Bolt Tensiometer. Bolt tensiometers, while being very durable pieces of equipment, do require periodic testing and calibration.
It is the Resident Engineer's responsibility to see that the tensiometer's working condition and calibration is verified annually. This testing and adjustment will be performed by the Materials Division upon request. Proper scheduling and coordination of this testing procedure will avoid unnecessary delays.
Correct usage of the tensiometer is as important as proper calibration. following tensiometer procedures are considered good practice:
The tensiometer should be flexed several times to warm up internal fluid.