Pozzolanic Reaction of Recycled Cementitious and Red Ceramic-Waste Aggregates with Hydrated Lime for Pavement Base Layer

Abstract

Cement addition and pozzolanic reaction in construction and demolition waste recycled aggregates can stabilize the base of pavements chemically. A way to control and explore the maximum benefits of it is necessary. This study establishes a mix between recycled cementitious and red ceramic-waste aggregates with hydrated lime to enhance pozzolanic reactivity in the material and achieve the best mechanical properties compared with those of a portland cement or recycled concrete aggregate itself pavement base layers. Chemical tests (Chapelle and thermogravimetry), physical tests (grain size distribution, density), and mechanical tests [unconfined compressive strength (UCS) and resilient modulus (RM)] were conducted. The increase of hydrates in the fine fraction of the mixes and the recycled aggregate itself correlated with the resulting increase in UCS and RM. The limited contribution of the self-cementing reaction of recycled cementitious aggregates was quantified, resulting in an UCS of 1 MPa and RM of 1,000 MPa. The pozzolanic reaction of cementitious and red ceramic aggregates with hydrated lime achieved an UCS of 8.4 MPa and RM of 2,800 MPa, values closer to those achieved by a portland cement stabilized pavement base (5.4 MPa and 4,500 MPa, respectively).