ASTM Standards ASTM D8490-23 pdf free download – Standard Test Method For Determining The Opening Size Of Circular Knit Geotextiles Using An Optical Method ASTM D8490-23 pdf free download - Standard Test Method For Determining The Opening Size Of Circular Knit Geotextiles Using An Optical Method. This test method ASTM D8490-23 is designed to measure the Image Opening Size (IOS) of... 09-22 Read More