Influence of execution defects on quality of cast-in-place concrete.

摘要

The purpose of this thesis is to investigate the influences of execution defects on the quality of cast-in-place concrete. In practical execution, there are many incorrect procedures, called execution defects, such as the early partial removal of forms to shorten the construction period and continuous concrete placement even during rain. Even if such execution defects are limited to part of the structure, there is the concern that the quality of the cast-in-place concrete is considerably affected by these execution defects.;In this thesis cast-in-place concrete for building work under a normal environment was chosen. Then local execution defects during the concrete placement and their effect on the hardened concrete, including the removal of the forms and curing time, were studied and researched. Specifically, four different situations were studied: (1) the mingling influence of fresh concrete of different quality placed on already hardened concrete, (2) the influence of rain during concrete placement, (3) the timing of the removal of the forms and how it affects the quality of the hardened concrete and (4) local differences in the curing conditions on the quality of hardened concrete.;This study resulted in guidelines being drawn up in "Guides for Practice Control to Execution Defects in Cast-in-Place Concrete for Building Work."