·Table of Contents ·Civil Engineering | New Test Method for Concrete Resistance on Abrasive ErosionElżbieta Horszczaruk , Włodzimierz KiernożyckiTechnical University of Szczecin Contact |
Fig 1: Scheme of the device for testing abrasive erosion of concrete |
(2.1) |
(2.2) |
Fig 2a: Changes of relative mass decrements, work of abrasive mixture- series I |
Fig 2b: Changes of relative mass decrements, work of abrasive mixture - series II |
Fig 2c: . Changes of relative mass decrements, power of abrasive mixture - series I |
Fig 2d: . Changes of relative mass decrements, power of abrasive mixture - series II |
(5.1) |
Differential dependence defining the mass decrement of the abraded concrete according to the work of the abrasive mixture W is expressed by the equation (5.2):
(5.2) |
Precise kinetics definition of the abrasive concrete wear, expressed in formula 5.2, should be search by assuming the parameters spectrum: a_{1}, a_{2}, ... a_{n}, determining local properties of abraded material. Assuming the discrete spectrum of parameters a, defining local "resistances" of material composition to abrasive wear, the equation (5.2) takes the following form:
(5.3) |
where: p_{i} determines the probability of parameter a_{i }occurrence.
After introducing the designation Q = M×
a, where M stands for abrasive power (W= M ×
t), the speed of concrete wear is defined by the following dependence:
(5.4) |
Gamma distribution was assumed for the description of variable Q (a) and the following expression defining the kinetics of abrasive erosion of concrete was formulated:
(5.5) |
Integrating the expression (5.5) within limits from t = 0 to t we obtain the dependence determining the mass decrement during the process of abrasion:
(5.6) |
where: defines the expected value of parameter Q.
The expected value of the variable a is expressed by the equation:
(5.7) |
Dependence (5.6) transformed to the form:
(5.8) |
Fig 3: Changes of relative mass decrements of I series concrete samples according to the work of the abrasive mixture |
Higher values of parameter E(a) of concretes with higher ratio w show their lower resistance to abrasive erosion. When one considers different speeds of the abrasive mixture - series II, the concrete samples of settled, constant composition are characterized by one expected value of the random variable a: E(a)=1.6x10^{-5} kg/ kJ independent of rubble movement speed (fig.4).
Fig 4: Changes of relative mass decrements of II series concrete samples according to the work of the abrasive mixture |
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