The effects of formwork types and curing period on the concrete surface quality

Quality of the surface concrete layer is important to keep durability of concrete structure. The beauty of concrete surface is also important. However, there are many cases that some initial defects occur. The past research has reported that using formworks coated by water repellent preparation and lengthening compaction time by vibration are able to reduce surface bubbles. In this research, we changed formwork types and curing periods. We considered what is affecting between surface bubbles and denseness of surface layer. As a result, surface bubble ratio depends on different formwork types, but the denseness of concrete didnt affect by types of formworks. On the other hand, quality of surface concrete strongly depended on curing periods. We measured elastic wave velocity by the ultrasonic speed measurement tool for estimating denseness of concrete. There was a good relationship between elastic wave velocity and air permeability and water permeability on surface concrete layer.