Study of the Effect of Compaction Rate on the Thermal Diffusivity of an Unbound Granular Road Material: The Case of Lateritic Gravel

Kocouvi Agapi HOUANOU^1, , Constant Euloge ADJAGBONI¹, Jean-Louis Comlan FANNOU², Kpomagbé Serge DOSSOU¹ and Antoine VIANOU¹

¹Laboratory of Energy and Applied Mechanics (LEMA), Polytechnic School of Abomey-Calavi (EPAC), University of Abomey-Calavi (UAC), Republic of Benin.

²Laboratory of Engineering Sciences and Applied Mathematics (LSIMA) of the National University of Sciences, Technologies, Engineering and Mathematics of Abomey (UNSTIM), Abomey, Benin

Cite this paper:
Kocouvi Agapi HOUANOU, Constant Euloge ADJAGBONI, Jean-Louis Comlan FANNOU, Kpomagbé Serge DOSSOU and Antoine VIANOU. Study of the Effect of Compaction Rate on the Thermal Diffusivity of an Unbound Granular Road Material: The Case of Lateritic Gravel. American Journal of Civil Engineering and Architecture. 2026; 14(4):146-154. doi: 10.12691/ajcea-14-4-2

Abstract

In the context of road construction in the intertropical zone, lateritic gravel is a predominant material due to its availability and geotechnical characteristics. This article examines the influence of compaction rate on the thermal diffusivity of lateritic gravel. For this study, samples of lateritic gravel from Cana Atchia, Zogbodomey commune, Zou department in Benin, were compacted to rates of 90%, 95%, 97%, and 100% in PVC cylinders. For each of these specimens, thermal diffusivity was determined using a numerical method that solves the heat equation in quasi-steady state based on data collected via an experimental setup comprising a heating lamp as the heat source and a data acquisition system with Type K thermocouples to monitor temperature changes within the material. At the same time, the CBR was measured at the various targeted compaction rates, both on unheated specimens and on those used to measure thermal diffusivity. The results obtained demonstrate a direct correlation between an increase in the compaction rate and an improvement in the material’s thermal properties. The average thermal diffusivity increased from 4.834×10⁻⁷m²/s at 90% compaction to 5.774×10⁻⁷m²/s at 100%. This increase is explained by the reduction in the material’s porosity, which facilitates better heat propagation through the densified particles. Additionally, it was noted that heating caused the CBR values to drop. However, the CBR increases with the compaction rate regardless of the type of specimen. This study confirms that optimizing the compaction of lateritic gravel is an effective means of improving its thermal performance, which reduces its strength performance. Better control of heat diffusion is essential for designing more stable and durable road infrastructure in tropical climates, thereby helping to reduce damage and long-term maintenance costs.

Keywords:
Lateritic gravel compaction rate thermal diffusivity CBR road infrastructure

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References:

[1]	Teng L., Liu H., Chu X., Song X. and Shi L, Effect of precipitation change on the photosynthetic performance of Phragmites australis under elevated temperature conditions. PeerJ. PeerJ Inc.; 2022; 10:e13087.
[2]	Nguyen D.D., Luo L.-J., Yang C.-J. and Lai J.-Y., Highly Retina-Permeating and Long-Acting Resveratrol / Metformin Nanotherapeutics for Enhanced Treatment of Macular Degeneration. ACS Nano. 17(1), 168‑83, 2023.
[3]	Hu J., Xu L., Yin T. and Ma T., Engineering Performance and Sustainability Assessment of Warm-Mix SBS-Modified Asphalt Mixture with Foaming Technique. J Transp Eng, Part B: Pavements. 150 (4) 0402405. 2024.
[4]	Zhang X., Wang Y., Zhou D., Yang C., An H. and Teng T, Comparison of summer outdoor thermal environment optimization strategies in different residential districts in Xi’an, China. Buildings. MDPI; 12(9) 13-32, 2022.
[5]	Kumar A., Gupta A., Anupam K., Singh A. and Premarathna S., “Mechanistic empirical studies of emulsion stabilized bases using finite element method”. Mechanics Based Design of Structures and Machines. 53(10) 6863-6890, 2025.
[6]	Zhang R., Sun L., Qiao Y., Sias J.E. and Dave E.V., Multidimensional comparative analysis of future climate change impacts on pavement infrastructure aging. Transportation Research Part D: Transport and Environment. Elsevier; 142. 104702. 2025.
[7]	Berraha Y., « Caractérisation expérimentale des propriétés thermiques de granulats de verre postconsommation et analyse par simulation numérique du comportement thermique d’une structure de chaussée avec couche de verre postconsommation», PhD Thesis, École de technologie supérieure, 2017. Consulté le: 15 mai 2025. [En ligne]. https://espace.etsmtl.ca/id/eprint/1903/.
[8]	Houanou K.A., Dossou K.S., P’kla A., Prodjinonto V., Adjagboni C.E. and Olodo E., Technical Parameters of the Cana-Atchia Lateritic Aggregate for Its Use in Road Engineering in Southern Benin. Current Journal of Applied Science and Technology. 21‑33, 2022.
[9]	NF P94-093, « Sols : reconnaissance et essais, détermination des références de compactage d’un matériau : essai Proctor normal-essai Proctor Modifié. », 20, 1999.
[10]	Houanou K.A., Adjagboni C.E., Dossou K.S. and Vianou A. Design of a Device for Measuring the Thermal Diffusivity of Granular Materials Using the Method of Numerical Solution of the Heat Equation. Open Journal of Civil Engineering. Scientific Research Publishing; 15(3) 442-452. 2025.
[11]	NF P94-078, « Sols : reconnaissance et essais, Indice CBR après immersion-Indice CBR immédiat-Indice Portant Immédiat », AFNOR, La Plaine Saint-Denis Cedex, 14, 1997.
[12]	Boutwell G. Effects of variation of fill construction on the material properties and the subsequent fill performance, Independent study Rep. School of Civ Engrg, Georgia Institute of Technology, Atlanta, Ga. 1961.
[13]	COLLET F., Benkhalla S., Khaled S., Hamieh N., Bart M. et Meslem A. De l’évaluation expérimentale à la simulation du comportement hygrothermique à l’échelle d’une brique de béton de chanvre. Academic Journal of Civil Engineering. 42(1) 242-253. 2024.
[14]	Hamieh N., Collet F., Meslem A., Rangeard D. and Le Borgne T. Investigating the Thermal Conductivity of Compacted Earth Blocks Versus Density and Moisture Content. In: Beckett C, Bras A, Fabbri A, Keita E, Perlot C, Perrot A, éditeurs. Second RILEM International Conference on Earthen Construction Springer Nature Switzerland; 52. 448‑457. 2024 [cité 19 mars 2026].
[15]	Hamieh N., Collet F., Meslem A., Rangeard D. et Leborgne T. Effet de la masse volumique sur la conductivité thermique et la valeur tampon hygrique de blocs de terre compactée. Academic Journal of Civil Engineering. 42(1) 638-647. 2024.
[16]	Hamieh N., Collet F. and Meslem A. An innovative drying method for on-site and precast walls–Efficiency in accelerating the drying of reduced-scale earth-lime-hemp composites. Construction and Building Materials. Elsevier; 4(13). 65-87. 2024.