Evaluation of PFWD and DCP as Quality Control Tools for Sub-Grade of GW and SW Soils

Abstract

<span>The Stiffness modulus is one of the necessary inputs in mechanistic-empirical pavement design and Quality Assurance/Quality Control (<span><em>Q Q </em><span><em>A C </em><span>) of pavement layers construction. The use of Portable Falling Weight Deflectometer <span>(PFWD) for measuring the stiffness modulus of unbound pavement layers is increasing worldwide. The modulus can <span>also be indirectly calculated by the results of other available devices. The Dynamic Cone Penetrometer (DCP) is an <span>easy-to-access device for evaluating the strength of unbound pavement layers in a cheap, easy and fast way. In this <span>study, the stiffness modulus of PFWD and penetration rate of DCP was correlated for the sub-grades ranging from <span>well-graded sand (SW), which is highly consisted of SiO<span>2 <span>and Al<span>2<span>O<span>3<span>, and well-graded gravel (GW) classification. <span>In addition, the results indicated that a good correlation exists between PFWD moduli and DCP results and also for <span>the precise evaluation of the SW soil modulus with a considerable amount of SiO<span>2 <span>and Al<span>2<span>O<span>3<span>, a coefficient factor, of <span><em>C </em><span>= <span>2.39 <span>, was presented.</span></span></span></span></span></span></span></span> </span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>