描述
Overview:
STDM-2 conforms to G B11971-89, GB81-85, JGJ053-94, ASTMC-469. It is mainly used to measure the elastic modulus of the test specimen. The instrument is simple, lightweight and easy to use in the test.
The main Main Specifications:
1.Application of elastic modulus of Concrete Test specimen….150×150×300mm,φ150×300mm 100×100×300mm, φ100×300mm
2.Dial gauge range …….0-1mm
3.The center distance from upper ring to lower ring…….150mm
4.The distance from lower ring to the bottom………75mm
Structure and its operation method:
The apparatus consists of an upper ring, a lower ring, a contact rod, a dial gauge and a fixing screw (see the attached drawing).
Before the the test, place the elastic modulus tester on a flat surface, unscrew the test specimen fixing screw, install the dial gauge, loosen the fixed plate fixing screw, remove the fixed plate, and The tester is positioned on the test specimen.. Place the tester together with the test specimen on the lower pressure plate of the pressure tester, the specimen is placed on the central of lower plate, the dial gauge to zero.
Start the press machine, when top board close to specimen, adjust the ball, makes contact with balance Continuously and evenly loaded to Pa at a rate of 0.2-0.3 mpa /s ( 40% of the expected damage load value of the test specimen),then unloaded at the same speed to zero，repeat this 3 times. When preloading, observe pressure machine and dial gauge are normal.
Both sides of the specimen deformation difference with dial gague shall not exceed 15 of the average deformation, can’t come different sign directions, when a 100mmx100mm cross-section specimen, the difference on both sides of deformation,
shall not exceed 20 of the average deformation, or made from hardwood to tap the ball seat adjustment, or adjust the specime position. Fourth loading with the above speed, the first to load PO early ( about 0.5MPA ), to maintain 30S, respectively, read dial gauge on both sides △O,Then loading to the PA, to maintain 30S, read both sides dial gauge △A respectively ,calculate both sides of the deformation increment △A-△O respectively, and calculate the average, to △4;after read △A ,at the same speed unloading to PO,to maintain 30S, read both sides dial gauge △00 respectively,Same as above steps, the fifth load, calculate the difference between△50 5and △4 shall not exceed 0.0002 ( L=150mm ),Otherwise, repeat the above steps until the difference between two adjacent loading deformation values meet the requirements, with the last △0 as the final value.Then remove the dial gauge, at the same speed loading to destroy the specimen, note the Cyclic axial compressive strength of Ra.
