STUDY OF SOIL-CEMENT MIXTURES AND THEIR USE IN ROADBASES

THIS REPORT WAS PRESENTED TO THE "NOVENO CONCURSO DE TEMAS VIALES", 1967. IT STUDIES THE INFLUENCE OF MATERIAL CHARACTERISTICS ON THE STRUCTURAL BEHAVIOUR OF GRANULAR ROADBASES STABILIZED WITH CEMENT. RECOMMENDATIONS ARE PUT FORWARD CONCERNING GRADING, PERMISSIBLE PLASTICITY, ETC. EQUATIONS ARE PRESENTED FOR DETERMINING THE COMPRESSIVE STRENGTH OF CYLINDRICAL SAMPLES, USING THE INITIAL MODULUS OF ELASTICITY AND PROPORTION OF CEMENT. THESE EQUATIONS ARE VALID FOR ALL TYPES OF CEMENT-STABILIZED SOIL OVER THE WHOLE RANGE OF FLEXIBILITY TO RIGIDITY. THE AUTHORS CONSIDER THAT A 3% CEMENT CONTENT (SEMI-RIGID BEHAVIOUR) IS THE PERMISSIBLE MINIMUM IF COHESION IS TO EXCEED INTERNAL FRICTION AND THE MIXTURE IS TO BE HOMOGENEOUS. THERE EXISTS A STRONG LINEAR CORRELATION BETWEEN THE COMPRESSIVE STRENGTH OF CYLINDRICAL SAMPLES AND THE INITIAL MODULUS OF ELASTICITY. ATTENTION IS DRAWN TO THE NEED OF TAKING ACCOUNT OF THE DYNAMIC MODULUS OF ELASTICITY IN THE CALCULATIONS AS THIS MODULUS TREBLES BETWEEN THE 28TH AND 60TH DAY FOR HIGH CEMENT CONTENTS.