Js. Guo et P. Waldron, An elastic model to quantify the effect of moisture on the mechanical properties of concrete at the time of test, MAG CONCR R, 53(3), 2001, pp. 151-162
This paper describes the detailed development of a mathematical model for d
etermining the effect of moisture on the mechanical properties of concrete
at the time of test. Based on the theory of elasticity it focuses on the st
ress distribution around spherical cavities in concrete filled with differe
nt types of inclusions. Results obtained from the mathematical model have a
ssisted in interpreting a number of experimental phenomena that have been t
he subject of long-term controversy. In particular the model explains why c
ompressive strength tests yield higher measured values for dry concrete spe
cimens than for otherwise identical wet specimens, while the measured value
s of static modulus exhibit the opposite effect. It also provides an explan
ation as to why measured tensile strength values obtained from direct tensi
on, tensile splitting or torsion tests are largely independent of moisture
content. The model provides an analytical tool for studying the interdepend
ence between the mechanical properties of concrete and its moisture content
. It also yields essential input for the computational simulation of the be
haviour of concrete structures that are subjected to large changes of moist
ure condition. Moreover; it provides a method for analysing the stresses at
the surface of any type of inclusion but particularly for cavities filled
with incompressible liquids under any stress field.