No abstract

Applicability of portable tools in assessing the bearing capacity of forest roadsKaakkurivaara T., Vuorimies N., Kolisoja P., Uusitalo J. (2015). Applicability of portable tools in assessing the bearing capacity of forest roads. Silva Fennica vol. 49 no. 2 article id 1239. 26 p. Highlights• The dynamic cone penetrometer (DCP) and light falling weight deflectometer (LFWD) are useful tools for measuring bearing capacity.• The measurement results are not same as with the falling weight deflectometer (FWD), but comparable. AbstractForest roads provide access to logging sites and enable transportation of timber from forest to mills. Efficient forest management and forest industry are impossible without a proper forest road network. The bearing capacity of forest roads varies significantly by weather conditions and seasons since they are generally made of poor materials and the constructed layers may be mixed with subgrade. A bearing capacity assessment is valuable information when trafficability is uncertain and rutting is obvious. In this study, bearing capacity measurements were carried out using the light falling weight deflectometer (LFWD), the dynamic cone penetrometer (DCP) and the conventional falling weight deflectometer (FWD). The aim was to compare their measurement results in relation to road characteristics and moisture conditions. Data were collected from 35 test road sections in four consecutive springs and during one summer. The test road sections had measurement points both on the wheel path and the centre line. The data show logical correlations between measured quantities, and the study presents reliable regression models between measuring devices. The results indicate that light portable tools, the DCP and the LFWD, can in most cases be used instead of the expensive falling weight deflectometer on forest roads.

No 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.

No abstract