01155548

Component

An integral component of the PCC module of the annual NHI Highway Materials Short Course is a series of independent and parallel evaluations of fresh and hardened properties for a single load of concrete. Six testing teams independently sample concrete from the truck and test the fresh concrete for temperature, slump, unit weight, and air content by pressure and by volume meter. Air temperature, wind speed, and humidity are also recorded for subsequent estimation of evaporation rate. The experiment has been repeated annually since its inception in 1990, with the objectives of demonstrating test procedures and the effect of various procedural factors on test results, showing by example the inherent variability in test results when the concrete itself is all from a single load; and in the case of fresh concrete, showing how results vary systematically with time after batching. This paper addresses only fresh concrete properties, showing the uncertainty and in particular the time-dependency in both slump and apparent air content. The relationship between slump and apparent air content, and the difference between air content as indicated by the AASHTO T152/ASTM C231 pressure air meter and the AASHTO T196/ASTM C173 volumetric air meter is also demonstrated.

01147878

10-3835

English

25p

2010

Transportation Research Board 89th Annual Meeting

DVD

Figures (16) ; References (4) ; Tables (3)

Air content; Concrete; Concrete curing; Concrete tests; Evaporation; Fresh concrete; Laboratory tests; Slump test; Temperature

Highways; Materials; Pavements; I32: Concrete; I52: Construction of Pavements and Surfacings

Transportation Research Board Annual Meeting 2010 Paper #10-3835

TRIS, TRB

Jan 25 2010 11:57AM