Fm. Bartlett et Jg. Macgregor, STATISTICAL-ANALYSIS OF THE COMPRESSIVE STRENGTH OF CONCRETE IN STRUCTURES, ACI materials journal, 93(2), 1996, pp. 158-168
Citations number
37
Categorie Soggetti
Construcion & Building Technology","Material Science
The relationship between the in-place compressive strength of concrete
in structures and specified strength f(c)' is investigated through th
e use of factors F-1 and F-2. Factor F-1, the ratio of the average str
ength of standard 28-day-old cylinder specimens to the specified stren
gth, is evaluated using data from 3756 cylinder tests representing 108
concrete mires produced in Alberta, Canada, between 1988 and 1993. Fa
ctor F-2, the ratio of average in-place strength to average cylinder s
trength, is evaluated using core and cylinder data representing 108 co
ncrete mires with strengths less than 55 MPa that were investigated by
others. A statistical description of the compressive strength of conc
rete in structures is derived that accounts for the inherent randomnes
s of Factors F-1 and F-2 and also the typical strength variation withi
n a specific structure. The probability of the in-place compressive st
rength of concrete in a 28-day-old column being less than f(c)' is app
roximately 13 percent. It is likely that a recalibration of the load a
nd resistance factors for the design of new structures in Canada based
on these findings would yield greater factored concrete strengths tha
n are currently in use.