Determination of the Slip-up Time for Slip-Form System using Surface Wave Velocity

摘要

The early setting time of concrete is a factor determining the slip up velocity of the slip-form system.rnAccordingly, need is for a technique evaluating the early setting time in order to secure the safety of the slipformrnsystem and the construction quality of concrete. The technique using surface wave velocity makes usernof the characteristics of the surface wave propagating along the surface and can assess the setting degree ofrnconcrete through the changes of the surface wave velocity. This technique is suitable for thick concreternstructures like the pylon. Therefore, this paper intends to estimate the early setting time by evaluating thernsetting degree of concrete using surface wave velocity so as to determine the slip up time of the slip-formrnsystem. Penetration resistance test and compressive strength test are performed first to clarify the relationshiprnbetween the early setting time of concrete and the compressive strength. Then, compressive strength test andrnultrasonic wave test are conducted to examine the relation between the compressive strength and the surfacernwave velocity. Continuous wavelet transform is adopted to measure the surface wave velocity. Numericalrnanalysis is carried out to demonstrate the appropriateness of the application of continuous wavelet transform.rnBased on these results, the propagation velocity of the surface wave required for the slip up of slipformrnsystem is suggested. Finally, a reduced model test of the slip-form system is conducted to verify thernfeasibility of the proposed surface wave velocity for the determination of the slip up velocity.