Page 146 - RoadCem Manual - PCT BV

• When a value higher than 500 􏰀m/m is achieved then it can be considered to use less RoadCem. Verification tests are requiered.
• When a value is lower than 500 􏰀m/m is achieved it is advisable to use more RoadCem. Verification tests are requiered.
5.7.5 Poisson Ratio
Poisson ratio measurement is often of interest for design criterion when a material's mechanical properties are evaluated.
When a sample of material is stretched in one direction it tends to get thinner in the other two directions.
Poisson's ratio is the ratio of the relative contraction strain, or transverse strain normal to the applied load, to the relative extension strain, or axial strain in the direction of the applied load.
Poisson's Ratio can be expressed as υ=-εt /εl
where
υ = Poisson's ratio
εt = transverse strain
εl = longitudinal or axial strain Strain can be expressed as
ε = dl/L where
dl = change in length
L = initial length
Typical value for concrete is 0.2 and for materials stabilized with Cement and RoadCem the typical values range between 0.2 and 0.3
The tensile test can provide two constants, Poisson's ratio and modulus of elasticity. The method involves lateral and transverse strain measurement simultaneously. Either strain gage or extensometers can be used for the strain measurements, but strain gages are preferred for their compact size. There are several limitations to Poisson determinations, but generally these are dictated by the material characteristics.
146