Continuous ultrasonic measurements during setting and hardening of building materials

Ultrasonic setting measurement is the study of how materials set or harden. Indeed, when mixed or combined, some materials undergo a change of their r heological properties if they are submitted to physical or chemical phenome na. Before use, these materials are liquid and they become solid when in us e, at temperatures close to ambient levels, for example, hydraulic binding materials (cement, whitewash, plaster). For each particular application, users and manufactures wish to Know the ev olution such materials undergo, for three reasons: the development fa new product (meeting a need), the largest possible reduction of setting,a time (economic criterion), the use of the material (moulding, transformation ...) without risking a ch ange of its propel-ties (quality-and safety-related problems). The ultrasonic setting-measurement device provides solutions to such needs. The method is based on tracking ultrasounds through an interface during th e process of solidification. Recording the change of transmissibility allow s monitoring,a the rheological evolution of the material. Some examples of the use of the ultrasonic setting measurement device are provided, on the b asis of laboratory measurements. A comprehensive study of the results of te sts using hydraulic binders and acrylic resins allows the determination of characteristic times corresponding to the evolution of the material in ques tion.