Laboratory Testing of Suction and Deformation Properties of Base Course Aggregates

Abstract

The most significant problem related to base course aggregates in Finland and in many other countries affected by seasonal frost is the development of permanent deformations, especially during the frost-thawing period. From 1996 to 2000, a series of research projects was carried out to examine the mechanical, thermodynamic, electrical, and chemical factors that affect the seasonal variation of strength and deformation behavior of base course aggregates. The test series included frost heave tests and normal as well as long-lasting cyclic-loading triaxial tests performed in situations simulating seasonal conditions of dryness, moisture, and the period following a freeze—thaw cycle. Also, chemical and suction properties of the selected aggregates were examined. Results show clearly that even though the aggregates were reflecting significantly different permanent deformation behavior, the resilient deformation properties of all tested aggregates were relatively good, and their resilient modulus values were not significantly lowered even during the thawing phase. Meanwhile, the suction properties of aggregates appeared to have a significant effect on the deformation behavior. Suction properties, in turn, result foremost from the fines content but also from chemical properties of the aggregate. A fairly simple tube suction test proved to function well in identifying the problematic aggregates and in defining appropriate binder types and their required amounts. Further, the results suggest that the properties of aggregates bound with emulsified bitumen are not necessarily improved when binder content is increased.

Comparison of Cyclic Triaxial Behavior of Unbound Granular Material under Constant and Variable Confining Pressure

“…Similar relationships ε p 1 ∼ q max /σ av 3 have been reported by several other researchers, e.g. [5][6][7]11,14,21,33,36,39,40,56,[61][62][63].…”

Shock-absorbing aggregates beneath playground equipment: grain properties and moisture content

“…In earth construction, it is generally known that the presence of fine particles between larger ones makes the compaction easier and increases density of the structure. The relation between fines content and permanent and resilient deformation properties is clearly shown in Kolisoja  et al ’s article 17. Concerning hardening, the work in real life with used loose-fill playground aggregates has revealed that in some cases material possesses a ‘cementing’ tendency where the particles adhere to each other forming a semihard crust on the top or to some distance below the surface of the shock-absorbing layer.…”

NDT Transportation

“…A series of research projects has been carried out in Finland and Texas where the relationship of the dielectric properties of Finnish and Texas base materials to their water content and strength and deformation properties was studied using a dynamic cone penetration (DCP) test, dynamic triaxial tests and a permanent deformation test (see Scullion, 1995, 1996;Kolisoja et al, 2002). A series of research projects has been carried out in Finland and Texas where the relationship of the dielectric properties of Finnish and Texas base materials to their water content and strength and deformation properties was studied using a dynamic cone penetration (DCP) test, dynamic triaxial tests and a permanent deformation test (see Scullion, 1995, 1996;Kolisoja et al, 2002).…”