Frost Action Predictive Techniques For Roads And Airfields Vol I

Vol. 1: Findings from a six-year field and laboratory program of frost-action research in four principal areas are summarized. Research on the first topic, frost-susceptibility index tests, led to selection of the Corps of Engineers' frost design soil classification system as a useful method at the simplest level of testing. At a much more complex level, a new freezing test combined with a CBR test after thawing is recommended as an index of susceptibility to both frost heave and thaw weakening. Under the second topic, a soil column and dual gamma system were developed and applied to obtain soil data used in improving and validating a mathematical model of frost heave, the objective of the third research topic.

Findings from a six-year yield and laboratory program of frost action research in four principal areas are summarized. Research on the first topic, frost susceptibility index tests, led to selection of the Corps of Engineers frost design soil classification system as a useful method at the simplest level of testing. At a much more complex level, a new freezing test combined with a CBR test after thawing is recommended as an index of susceptibility to both frost heave and thaw weakening. Under the second topic, a soil column and dual gamma system were developed and applied to obtain soil data used in improving and validating a mathematical model of frost heave, the objective of the third research topic. The model was effectively improved, a probabilistic component was added, and it was successfully tested against field and laboratory measurements of frost heave. A thaw consolidation algorithm was added, which was shown to be useful in predicting the seasonal variation in resilient modulus of granular soils, the objective of the fourth topic. A laboratory testing procedure was developed for assessing the resilient modulus of thawed soil at various stages of the recovery process, as a function of the applied stress and the soil moisture tension, which increases as the soil gradually desaturates during recovery. The procedure was validated by means of appropriate analyses of deflections measured on pavements by a falling-weight deflectometer. Frameworks for implementing findings from the principal research topics are outlined. Keywords: Airfields, Freezing thawing, Frost heave, Frozen soil, Resilient modulus, Roads.

Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

At first glance, roads seem like the simplest possible geotechnical structures. However, analysis of these structures runs up against complexities related to the intense stresses experienced by road surfaces, their intense interaction with climate, and the complicated behavior of the materials used in road construction. Modern mechanistic approaches to road design provide the tools capable of developing new technical solutions. However, use of these approaches requires deep understanding of the behavior of constituent materials and their interaction with water and heat which has recently been acquired thanks to advances in geotechnical engineering. The author comprehensively describes and explains these advances and their use in road engineering in the two-volume set Geotechnics of Roads, compiling information that had hitherto only been available in numerous research papers. Geotechnics of Roads: Fundamentals presents stresses and strains in road structures, water and heat migration within and between layers of road materials, and the effects of water on the strength and stiffness of those materials. It includes a deep analysis of soil compaction, one of the most important issues in road construction. Compaction accounts for only a small proportion of a construction budget but its effects on the long-term performance of a road are decisive. In addition, the book describes methodologies for nondestructive road evaluation including analysis of continuous compaction control, a powerful technique for real-time quality control of road structures. This unique book will be of value to civil, structural and geotechnical engineers worldwide.