**1. Introduction**

The growing urbanization process in cities leads to an increase in impermeable areas, generating changes in the natural characteristics of watersheds. Consequently, the recharge of springs and groundwater is compromised, and as the volume of surface runoff increases, the risks of floods and inundations occur. An alternative for integrated rainwater managemen<sup>t</sup> is using porous pavements and surfaces.

The pavement layer surface mainly comprises porous asphalt mixtures, produced with a high amount of air voids and a percentage of coarse aggregates to form an opengraded granulometry and allow water to flow through it. The open gradation results in higher voids (18–25%) compared to densely-graded mixtures [1,2]. On the other hand, fine aggregates contribute to mixture strength and durability, but increasing their proportion compromises the permeability, which is negligible if the void content is less than 14% [3].

Zhang et al. asserted that studies had shown the benefits of porous mixtures compared to dense ones. Due to the interconnected porosity, the water flows out of the pavement during rainfall, avoiding accumulation on the surface. The road safety improvements include increased skid resistance and reduced hydroplaning [4].

The infrastructure can introduce low-impact development models through increasing permeable areas such as green spaces, porous pavements, and water systems. These models allow rainwater to be absorbed, retained, and released to reduce runoff volume and peak flow, slow down runoff speed, replenish groundwater, and filter rainwater pollutants [5,6]. However, the water that precipitates on the pavement surface carries contaminants and powdery materials (runoff), which, over time, lead to the progressive clogging of the voids.

Due to clogging, functionality is affected, and the porous pavement (or surface) cannot facilitate drainage. Additionally, the porous surface suffers damage due to water stagnation inside. The rate of clogging depends on factors such as the pavement surface, void content,

**Citation:** Garcia, E.S.H.; Thives, L.P. Intervention Time of Porous Asphalt Mixture Evaluation to Prevent Clogging. *Environ. Sci. Proc.* **2023**, *25*, 3. https://doi.org/10.3390/ ECWS-7-14196

Academic Editor: Athanasios Loukas

Published: 14 March 2023

**Copyright:** © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

traffic load, pavement slope, maintenance measures adopted, and environmental and local conditions [7]. An evaluation of the progression of clogging can be performed in the field or laboratory using permeameters.

Porous surface pavement layers are beneficial as they contribute to stormwater managemen<sup>t</sup> by reducing surface runoff. On the other hand, the voids in porous layers clog over time, and the permeable characteristics decrease. Because of this, road agencies avoided applying the porous surface layer to the pavement.

In order to contribute to advancing the use of porous mixtures as a pavement surface layer, the primary motivation of this study was to evaluate the clogging by simple permeability tests. Thus, permeability reduction enabled establishing the needed intervention time to restore porous mixtures permeable characteristics. This study aims to evaluate the maximum time for an intervention in a porous mixture to recover its permeable properties before clogging.
