Title:
Role of Aggregate Packing on Pore Networks and Transport Properties of RAP-Based Concrete Mixtures (Prepublished)
Author(s):
Ritika Kamboj and Solomon Debbarma
Publication:
Materials Journal
Volume:
Issue:
Appears on pages(s):
Keywords:
aggregate packing; durability performance; moisture ingress; pore structure; RAP concrete; transport properties; X-ray computed tomography
DOI:
10.14359/51752024
Date:
8/26/2026
Abstract:
The heterogeneous pore structure and weak interfacial transition zones associated with reclaimed asphalt pavement (RAP) aggregates adversely affect the durability of cement concrete. This paper quantitatively evaluates the influence of aggregate packing on pore network characteristics and transport properties of RAP concrete. Concrete mixtures were proportioned using a conventional particle size gradation (PSG) method and a particle packing–based method (PPM). X-ray computed tomography was used to quantify pore structure and connectivity, while sorptivity, open porosity, ultrasonic pulse velocity, and electrical resistivity were measured to assess transport behavior. Compared to PSG mixtures, RAP concrete mixtures designed with the PPM approach showed a more refined pore network, shorter pore throats, and higher tortuosity due to better aggregate packing and reduced meso-scale pore connectivity. These microstructural changes resulted in significant reductions in sorptivity and open porosity, along with improved ultrasonic pulse velocity and electrical resistivity. The results demonstrate that packing-optimized mixture proportioning effectively mitigates transport-related durability concerns in RAP concrete.