2.4　Three Point Bending Tests

Three-point bending tests(TPB)were used to evaluate the fracture properties of PC and GC mortar/concrete beams.The beam dimensions were 100 mm×100 mm×515 mm with a spanto-depth ratio of 4.0.Each beam specimen was precut with a notch in the middle,40 mm deep and 3 mm wide.The configuration of the beam specimens is illustrated in Figure 3.Three identical specimens were prepared for each type of mix,thus a total of 63 beams were tested.The crack mouth opening displacement(CMOD)and crack tip opening displacement(CTOD)were measured using clip gauges clamped at both the mouth and the tip of the precut notch.The mid-span displacement(δ)of the beam was detected by two linear variable dif ferential transformers(LVDTs).The displacements of the two supports were also measured by the LVDTs to remove the effect of support settlement on the mid-span displacement.To obtain the complete load-displacement(P-δ,PCMOD,P-CTOD)curves,a closed-loop servo controlled hydraulic jack of 100 k N capacity was used and operated at a stable and slow loading rate of 0.02 mm/min.

Figure 3　Configuration of three-point bending test beam(unit:mm)