Perspectives for “Materials for Building”

Univ.-Prof. Dr.-Ing. Horst-Michael Ludwig (Fig. 1) gave his inaugural lecture on October 14, 2010 in the context of a formal celebratory event held in the packed auditorium of the “Neue Weimarhalle” Congress Center in Weimar, following his appointment as University Pro­fessor to the Chair of ­“Materials for Building” at the Bauhaus University of Weimar with effect from November 1, 2009. Prof. Ludwig had ­already succeeded Prof. Dr.-Ing. habil. Jochen Stark, the first Vice-Chancellor of the F.A. Finger-Institute for Building Materials ­Science, on April 1, 2010.

Those in attendance, including numerous distinguished officials of the university, such as the Chancellor, Prof. Dr.-Ing. Heiko Schultz, the Dean, Prof.-Dr. Ing. Hans-Joachim Bargstädt, the Prorector, Prof. Dr.-Ing. Karl Beuke, and former Chancellor Prof. Dr.-Ing. habil. Hans-Ulrich ­Mönnig, were welcomed by Dr.-Ing. Hans-Bertram Fischer, who also provided, in a tongue-in-cheek “astrological excursion”, an outline of the salient points in Prof. Ludwig’s career, concluding by answering unequivocally in the affirmative, in the case, at least, of this outstanding building-materials scientist, the question “Are our lives really predetermined?”.

The proceedings were then initiated by Prof. Heiko Schultz, who gave the audience an insight into the history of the Bauhaus University from the foundation of the former Weimar Academy of Art (1860), the “Bauhaus” movement by Walter Gropius (1919) and, ultimately, the Bauhaus University (1956), up to the present-day, with its four faculties of Architecture, Civil Engineering, Art and Design, and Media. Prof. Schultz also expressed his satisfaction that Prof. Ludwig’s inaugural ­lecture was to take place during the 150^th anniversary year of the Bauhaus University, in view of the fact that events of this nature had become regrettably rare. As he stated, the university considers itself fortunate to have obtained in Prof. Ludwig in a selected procedure a highly competent researcher and uni­versity lecturer, whose lectures, it was to be hoped, would prove a magnet for a large number of students for many years to come.

The guests then heard with great interest the deliberations of the incoming professor for “Materials for Building”, who firstly focused on the Institute for Building Materials ­Science and its future orientation. The institute bears the name of F.A. Finger, appointed Professor for Building Materials Science, Civil Engineering and Statics in 1944, who then proceeded to create a separate discipline of building materials under innovative categorizing criteria. It was thanks to him that a Faculty of Building Materials Science und Building Materials Technology, at which a unique specialized course of training in this field was achieved, could be founded at the University of Weimar in 1953. The foundation of the F.A. Finger-Institute for Building Materials Science followed in 1995 as part of the Faculty of Civil Engineering, headed by Prof. Ludwig since April 1, 2010. Other departments of the faculty, such as Process Engineering and Recycling, as well as Building Chemistry, are also planned, to complement the Materials for Building and Polymeric Construction Materials departments. Numerous research projects in the fields of building chemistry, concrete, alkali/silica reactions, gypsum, and the supra-disciplinary topics of “Structure analysis”, “Mineralogy”, and “Plaster/mortar – new materials for art”, which in many cases have links to industry, have to a large degree made it possible to accrue the necessary finances autonomously.

Prof. Ludwig’s inaugural lecture, “Materials for Building in the 21^st century” followed, with Prof. Ludwig postulating that concrete, employing cement as its binder, will continue to dominate in this period. As he remarked, global consumption of concrete is now 8 billion m³, compared to only 40 million m³ in 1900, and no end to this progression is yet in sight. The sole definitive factor in this predominance, he noted, is price, especially since the energy input necessary for production is highly rational compared to other building materials. To this must be added cement, as a super binder-adhesive, a factor based, above all, on the structure of the CSH phases. Global cement production is set to double from 2005 to 2050.

Outline examinations of the following key topics then followed:

– Concrete input materials: Process engineering optimization of kilns and grinding systems has largely been completed, and potentials are now perceived in mill technology (e.g. agitator ball mills) and the replacement of fossil fuels. Research is needed into composite materials in terms, for example, of their diverse properties, durability, availability, potential substrates such as prepared ferrous metallurgical slags, dolomite powders, calcined clays, rice husk ash and the use of alternative binders, including reactive aluminosilicates, supersulfate cement, Ca-sulfoaluminate and belite cement.

– Concrete additives: Thanks to their high liquefaction effect compared to lignin sulfonate, the use of polycarboxylates permits much higher early strengths; adjustment of properties is possible via chain length. The dependence of effect on the particular cement type is problematical, however.

– Concrete properties: Workability, strength in compression (with a rising trend), concretes incorporating individually tailored properties, control of reaction kinetics, synthetic CSH phases as nucleating agents, and durability (with problems still remaining in the field of the alkali/silica reaction (ASR), development of a climate-change exposure chamber for simulation of ASR-induced damage by means of measurement of expansion as a function of time, effective failure minimization by means of the use of blast-furnace cement – dilution effect – or fly ash – fixing of alkalis in the CSH phases).

– Modern analytical procedures: Examination of all the methods used at the Finger Institute, such as ESEM, the NOVA^® Nano SEM (Fig. 2), micro X-ray fluorescence analysis, quantitative XRD, ICP instruments for determination of pore solutions, and thermodynamic modeling.

In his summary of future prospects, Prof. Ludwig gave the audience an outline of the perspectives for “Materials for Building”, which he summarized under the following topic focuses:

– Production of low-CO₂ cements

– Recyclability of building materials

– Environmental impact

– Sustainability

– Cement multifunctionality (thermal insulation, self-cleaning capability, switched hydration processes)

– Minimization of reinforcement steel via replacement with textiles or other materials

– Multifunctional materials (e.g. TiO₂ as a photo-catalyst)

– Chronologically controllable setting and curing processes

A broad range, therefore, of interesting research fields, which will be reflected not only in Prof. Ludwig‘s lectures, but will, no doubt, also provide a large number of graduands and PhD students with thesis topics.