Elastic modulus is the ratio between tension and the corresponding deformation measured in the direction of tension. For materials, such as concrete, for which the stress - strain diagram is not rectilinear, the following is defined: secant elastic modulus between two stresses that determined by the slope of the secant to the stress - strain diagram between the two stresses considered; tangent elastic modulus for a given tension that determined by the slope of the geometric tangent of the stress diagram - Deformations in correspondence with that tension. in this standard the determination of the secant elastic modulus between two tensions is considered after a certain number of load cycles (repeated until stabilization); due to the properties of the material under examination and the test methods it is advisable to start from a base voltage other than zero. The compressive secant elastic modulus can be determined on concrete specimens: prepared in the laboratory with fresh concrete (see UNI 6128 and UNI 6129); prepared on site with fresh concrete (see UNI 6126 and UNI taken from structures (see UNI 6131). Specimens: shape, dimensions, number, curing. Equipment. Procedure. Expression of results.
UNI 6556-1976 history
1976UNI 6556-1976 Tests of concretes. Determination of static modulus of elasticity in compression.