The design, fabrication and implementation of a computer-controlled exposure and testing apparatus for building joint sealants are described in this paper. This apparatus is unique in its ability to independently control and monitor temperature, relative humidity, ultraviolet (UV) radiation and mechanical deformation. Each of these environmental factors can be controlled over a wide range of conditions with deviations from the control value being small during long term experiments (a month or more). Moreover, since specific deformations can be generated, in-situ mechanical characterization tests can be performed without removing specimens from the chamber. The controls for temperature and humidity were implemented via a precision temperature regulator and proportional mixing of dry and saturated air; while a highly uniform UV radiation was attained by attaching the chamber to an integrating sphere-based radiation source. A computer-controlled stepper motor and a robust transmission system were used to provide precise movement control. The reliability and effectiveness of the apparatus were demonstrated on a model sealant material. The results clearly show that this apparatus provides an excellent platform to study the durability of building joint sealants.
Citation: Review of Scientific Instruments
Pub Type: Journals
Sealant, polymer, instrument, stress, strain, testing, Ultra Violet, Humidity, Temperature