Björn Höhlig
Leipzig University of Applied Sciences, Germany
Title: Temperature-controlled heating and hardening of fresh concrete with an innovative high-frequency technology
Biography
Biography: Björn Höhlig
Abstract
CO2 emissions, energy costs and cement consumption in the production of precast concrete elements can be decreased substantially with the aid of radio wave heat treatment, an innovative high-frequency (HF) technique for the controlled heating of fresh concrete. This procedure generates a second internal heat source, alongside hydration heat, by applying radio wave technology (the operating principle is similar to that of microwaves) during the concrete curing process. An accelerating hardening of the concrete will be achieved. The application of HF technology and, in particular, electromagnetic waves in the radio-frequency range to heat treating fresh concrete and to enhance its early strength is an efficient, energy-saving alternative to conventional heat treatment procedures. This is possible by heating the fresh concrete in a targeted, homogeneous way and by avoiding sluggish heat conduction processes as the dominant means of heat induction. From a concrete technology point of view, an extremely precise controlling of the concrete’s temperature offers the advantage of maintaining strict adherence to limiting temperatures. This means that problems with durability (e.g. secondary ettringite formation) can be avoided and long-term damage to the concrete elements prevented. It is also worth mentioning the point that optimum conditions can be attained in each complete component because of the temperature profile’s homogeneity, which must be appreciated as a unique feature of the radio wave procedure.