Portable Pressure Device to Evaluate Lateral Formwork Pressure Exerted by Fresh Concrete

Abstract

Use of a reliable and accurate measuring system to determine lateral pressure exerted on formwork by self-consolidating concrete can lead to economic and safe formwork systems. In this paper, a portable and field-compatible pressure device is developed to enable factors affecting lateral pressure of fresh concrete on formwork system to be explored prior to conducting onsite full-scale tests. The pressure device requires a sample of 16 L of fresh concrete to determine lateral pressure envelope that can be exerted by a concrete column of up to 13 m in height. The pressure device enables the simulation of such concrete head using an overhead pressure exerted onto the fresh concrete. A number of parameters are used to validate the pressure device, including placement rate as well as mix designs of various paste volume, slump flow, ratio of water to cementitious material, maximum size of aggregate, and dosages of chemical admixtures. The test results indicated that the repeatability of the lateral pressure values obtained using the pressure device shows relative error of about 7%. The validation of the pressure device clearly showed that the device adequately reflects the effect the various factors affecting lateral pressure characteristics of fresh concrete.