Two new standards from the Geosynthetics committee of ASTM will help define properties that can be used in the design of geosynthetic reinforced pavement. I know in my practice in Arizona, ADOT simply allows a boost of Resilient Modulus (R-Value) of 10 when biaxial geogrids are used. Perhaps in time this will lead to a design method to account for the geosynthetic reinforcement in a more analytical way. [Source: Geosynthetics Magazine]
Articles
The Curious Case of No. 57 Stone
The American Society for Testing and Materials, or ASTM, No. 57 stone is often used as sub base fill material below road surfaces and buildings. It is a fragmented stone with angular edges and is regularly utilized as a drainage layer when used with geotextile fabric. Although the material is touted by many as "self-compacting," excess voids left from zero compactive effort in locations with little confinement may not eliminate the possibility of future settlement. What happens when the environment above the No. 57 stone causes it to settle?
[Editor] Read on for the answer to this interesting question in the case of settlement of a structure at the University of North Carolina at Chapel Hill. The contributed article by Katherine Witt describes how URETEK Mid-Atlantic used their high-density polyurethane resin to stabilize the No. 57 stone beneath a settled foundation as well as lift the surrounding slab back into place. [/Editor]
Standards and Codes
ASTM Updates March 2009
Our monthly update on new and revised ASTM standards that relate to geotechnical engineering, materials testing, hydrogeology, geosynthetics and related disciplines. This month there are a few notable revisions, including D1452 for Auger Borings, D3385 for Double-Ring Infiltrometer and D4595 for determining tensile properties of geotextiles by the wide-width strip method. There are also a few other geotextile, groundwater, lime, masonry and terminology standards that were added or updated. Click through for the full list.
Standards and Codes
ASTM Updates April 2009
Our monthly ASTM standards update for those in the geotechnical, geo-environmental, hydrogeology and geo-construction fields. This month there are some new standards related to structural cementitious panels, revisions to standards related to slate and dimension stone, and a reapproved standard for monitoring well protection among others. Click through for more info.