Some observations on microcracking in concrete subjected to various loading regimes

✍ Scribed by P Stroeven

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 73 KB
• Volume: 35
• Category: Article
• ISSN: 0013-7944
• DOI: 10.1016/0013-7944(90)90251-b

✦ Synopsis

Measuring the complete load displacement curve of tensile loaded unnotched specimens makes great demands on the test device. A very stiffened testing machine, the use of a load bypass beside the specimen for achieving high speed adjustment and an electronic indication system for detecting subcritical crack accumulations in material structure are needed. The measuring length on a prismatic shaped specimens is divided into two sections. The damage process begins with microcrack accumulations in a certain zone whose position is not known beforehand. If these microcrack accumulations occur, the signal of elongation increases rapidly while the signal in the second section will decrease. The "differential signal" of these two sections is the indicator for detection of the start of crack opening. The testing machine can be regulated by decreasing the load before crack accumulations become critical and form a macrocrack.