Comparison of accelerated laboratory curing and maturation under uncontrolled conditions of gravel emulsions using a nonlinear weighted least-squares predictive model

ABSTRACT

Cold-asphalt mixtures (CAMs) are evolved materials whose mechanical strength increases with their maturation. The relationship between CAM field maturation and laboratory-accelerated cure procedures is not well understood. Furthermore, there is controversy on the recommended methodology for laboratory-accelerated cure. So, in this work, the accelerated curing protocol for a CAM-type gravel emulsion was examined, and its uncontrolled maturation and performance were contrasted. For this, the mixture was subjected to either accelerated curing (from 0 to 7 days in a 50 °C oven) or natural curing (from 0 days to 6 months at 20 3 °C in the laboratory and at an unfixed temperature outside the laboratory). We analysed, as functions of time, the moisture, indirect tensile stiffness modulus (ITSM), and moisture damage resistance. A curing protocol of 2 days at 50 °C yielded ITSM values closer to those obtained under uncontrolled conditions. Nevertheless, total maturation of the mixture was achieved after 3.5 days of curing. The nonlinear weighted least-squares method yielded an expression that better predicted the performance of the gravel emulsion for the first six months of life. The model parameters were easily fitted using ITSM measurements derived from samples cured for 2 days in a 50 °C oven.

KEYWORDS:

• Cold-asphalt mixture
• gravel emulsion
• evolutive material
• uncontrolled maturation
• accelerated curing protocol
• nonlinear weighted least squares

Acknowledgements

The EMULCELL project was co-financed by the Centre for Industrial Technological Development (CDTI), the Ministry of Economy and Competitiveness-Government of Spain, and the European Regional Development Fund (FEDER) (Ref. IDI-20171097).

The authors would also like to thank ‘Repsol’ and ‘Áridos de Astariz’ for kindly providing the necessary materials to carry out the research.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Declaration of interest statement

There are no relevant financial or non-financial competing interests to report.

Data availability statement

The data that support the findings of this study are available from the corresponding author [A.R.P] upon reasonable request.

Additional information

Funding

This work was supported by Centre for Industrial Technological Development (CDTI), the Ministry of Economy and Competitiveness-Government of Spain, and the European Regional Development Fund (FEDER) : [Grant Number IDI-20171097].

Notes on contributors

Ana María Rodríguez Pasandín

Ana M. Rodríguez Pasandín is a civil engineer with MSc and PhD degrees. After working for almost seven years in a private company and developing projects for the construction of linear infrastructures, in November 2007, she began to develop her professional career at the School of Civil Engineering of the Universidade da Coruña (UDC), where she is an Assistant Professor. She teaches subjects from the area of engineering and transportation infrastructure, including those related to the layout of roads, pavements, and traffic. Her research focuses on the design and analysis of sustainable materials for road pavements (half-warm mix asphalt, cold mix asphalt, etc.). She published 31 papers indexed in the JCR (16 Q1).

Juan José Galán-Díaz

Juan José Galán-Díaz is a physicist with intense research experience in the field of surface-active materials and their applications and several resulting articles in indexed journals (JCR). He is currently an Assistant Professor at the School of Civil Engineering.

Luís Manuel Sousa da Silva

Luís M. S. Silva is an Assistant Professor of chemical engineering at the Polytechnic of Porto, Portugal. He earned his 5-year degree in Chemical Engineering from the University of Porto (1990) and received his PhD (1999) from the same university. He is a member of the Portuguese group for the integration of processes (GNIP) and the Portuguese Chemical, Petrochemical, and Refining Association (APQuímica).

Pablo Orosa Iglesias

Pablo Orosa Iglesias received MSc and PhD degrees in civil engineering from the Universidade da Coruña (UDC) in 2016 and 2022, respectively. He also worked as a teaching assistant in road design subjects and collaborated in educational innovation tasks. His field of expertise is sustainable asphalt pavement engineering.

Ignacio Pérez Pérez

Ignacio Pérez Pérez is a doctor in civil engineering (Polytechnic University of Madrid). He is an Assistant Professor at the School of Civil Engineering, Universidade da Coruña (UDC), where he teaches highway engineering. Doctor Pérez is an expert in pavement engineering, with numerous publications in international scientific journals on the mechanical behaviour of the materials used in pavements (asphalt concrete mixtures, unbound granular materials, etc.) and the use of recycled materials in pavements. Assistant Professor Pérez has seven years of on-site work experience in companies involved in the construction of roads, railways, etc.