Stabilization of Coarse Aggregates with Traditional and Nontraditional Additives

Abstract

High-quality coarse aggregates are routinely used for the surface, base, and subbase layers in paved roads or the surface course in unpaved low-volume roads. Unfortunately, high-quality aggregates meeting stringent material specifications are becoming increasingly costly and difficult to find within reasonable distances of road construction projects. Various stabilization technologies can be employed to improve the mechanical properties of available aggregate materials, providing environmental and economic benefits. This investigation used three laboratory test methods to evaluate and compare all the existing kinds of additive technologies suitable to stabilize a coarse-graded road unbound layer. Two traditional solutions (cement and bitumen) and eleven nontraditional solutions (categorized as either brine salts, clay binders, organic nonpetroleum products, organic petroleum products, or synthetic polymers) were included. Repeated load triaxial tests were performed to evaluate the dynamic behavior of the untreated and treated aggregates in terms of their resilient modulus and the resistance against permanent deformation. A modified version of the rolling bottle test was used to appraise the stripping resistance offered by each additive. A microscopic analysis was conducted to visually evaluate the propensity of the additives to adequately coat the surface of the aggregates. All the stabilization technologies improved the material stiffness, with the most significant improvements produced by calcium chloride salt, bentonite, lignosulfonate, and cement mixed with a mineral mixture. The stabilization additives effectively reduced permanent deformations, except for the specimens stabilized with polyurethane and bitumen. Finally, the polymer-based additives and bitumen demonstrated very good resistance to stripping, with polyurethane providing the smallest mass loss. This study documents that nontraditional stabilization technologies can provide effective alternatives to the traditional stabilizers and documents that a "one-size-fits-all" additive agent is unlikely to be developed.

Dataset of mechanical properties of coarse aggregates stabilized with traditional and nontraditional additives: Stiffness, deformation, resistance to freezing and stripping

“…The tested rock aggregate material derives from Vassfjell, Heimdal, Norway. The thirteen binder technologies are obtained from industrial producers and the categories these additives belong to are representative of all the existing commercial products suitable to stabilize coarse aggregates [2] , [3] , [4] , [5] , [6] , [7] . The testing campaign was performed in the laboratories of the Department of Civil and Environmental Engineering (Norwegian University of Science and Technology, Trondheim, Norway) to characterize the mechanical properties of unstabilized and stabilized rock aggregates.…”

“…The analysed data can lead to the evaluation and comparison between all the binder treatments in terms of resilient modulus and resistance against permanent deformation. The particle size distribution used for the tests varied from 0 mm to 32 mm and thus corresponded to a typical road base layer; different quantities of binder ranging from 1% to 4% were mixed with 12 000 g aggregates for each RLTT sample [ 2 , 3 ]. The stress path applied is a combination of triaxial stress σ t and deviatoric stress σ d as reported in Table 7 ; each loading step applies 10 000 loading repetitions.…”

“…The procedures adopted to perform each FT repetition were: specimen submersion in water (23°C, 5 minutes), retrieval and release of water excess (23°C, 5 minutes), freezing (-15°C, 24 h) and thawing (23°C, 24 h for RLTT samples and 40°C, 48 h for Marshall samples) [ 2 , 3 ].…”

“…Very few previous investigations have comprehensively compared the mechanical properties of both traditional and nontraditional technologies in a single independent study. The dataset has a size of 3 772 MB and revolves around the binder application to coarse-graded aggregates as thoroughly discussed in the two corresponding research articles [ 2 , 3 ]. The objective of this data article is three-fold: to describe how the data have been obtained in the laboratory, to explain the taxonomy adopted to store the dataset on the public repository Mendeley Data and to highlight how stakeholders (e.g., transport agencies, contractors, researchers, manufacturers of the stabilizers) can benefit from it.…”

“…The dataset derives from a thorough investigation assessing the mechanical properties of all the existing binder technologies suitable for stabilizing coarse-graded aggregates [ 2 , 3 ]. The data were collected by performing four laboratory test operations: Repeated Load Triaxial Test (RLTT) both before and after the action of 10 Freeze-Thaw (FT) cycles, weight measurement of Marshall specimens during 10 FT cycles and a modified version of Rolling Bottle Test (RBT).…”