Large-size aggregates for road construction—a review of standard specifications and test methods

Abstract

Construction aggregates are essential structural components in road structures, whether in unbound form or combined with cement or bitumen. Specifications and test methods for aggregates are standardised, but current standards are limited concerning the maximal aggregate size for which they apply. This paper deals with standard specifications and test methods for large-size road construction aggregates, reviewing a new Norwegian national standard for large-size aggregates. The standard test methods and their validity and applicability for use on large-size aggregates for road construction are evaluated. The differentiation between requirements regarding the rock material (single rocks) and the aggregate product is specifically discussed, as is the specific challenges related to the use of all-in aggregates. Current standards for construction aggregates do not cover all challenges related to description and quality assessment of construction aggregates. Quality assessment is particularly challenging for large-size aggregates, and this topic needs a better description by international standards. Field methods and digital image processing are introduced as solutions for some of the practical challenges related to sampling for large-size aggregates. The new Norwegian standard could be the first step towards a European standard for large-size aggregates.

Wear and Fragmentation Resistance of Mineral Aggregates—A Review of Micro-Deval and Los Angeles Tests

“…Fladvad and Ulvik [ 21 ] notice a disadvantage of using limited dimension ranges of the tested aggregate. The wear and fragmentation test method does not allow aggregate tests in wider grain size ranges.…”

“…Knowledge of their mechanical properties allows predictions of the behavior of aggregates under different loads. Aggregates are subjected to significant degradation during their entire lifetime and, according to Teymen [19], Koohmishi [20], and Fladvad and Ulvik [21], this is particularly important if they are used as ballast in railroads, as basecourse in roads, or as a component of concrete. Additionally, knowing the physical and mechanical parameters of aggregates allows evaluations of the strength of concrete mixtures or bituminous asphalt mixtures [8,10,15,22].…”

Special issue on construction aggregates

“…Disability to cover all differences resulting from local/regional/national conditions can make serious problems when trying to use some specific types of aggregates. This question has been highlighted in the current special issue by Fladvad and Ulvik (2019) by discussing the issue related to sampling, testing and usage of large-size aggregates (i.e. above 90 mm in diameter).…”

“…above 90 mm in diameter). Fladvad and Ulvik's (2019) argument is that some of the conventionally advised test procedures are not adoptable for these large-size aggregates which implies application of…”

Permanent deformation modelling of large-size unbound pavement materials tested in a heavy vehicle simulator under different moisture conditions

“…In Norway, local aggregate resources originating from tunnels and road cuts are often utilised in construction projects (Aarstad et al, 2019). Subbase materials with particle sizes > 90 mm are commonly used, even though such materials are outside the scope of European standards and lack suitable quality assurance methods (Fladvad & Ulvik, 2019). Due to experience with frost heave problems caused by excess fines, a practice has developed where all fine material is sorted out from the large-size aggregates used in the subbase layer (Aksnes et al, 2013).…”