An integral design concept for ecological self-compacting concrete

This Thesis addresses an alternative design concept for Self-Compacting Concrete (SCC). SCC is a special type of concrete with superior workability, which flows and compacts in all corners of a formwork just by influence of gravity. Introduced to concrete world in late 1980s, SCC has been enthusiastically received by researchers and was referred to be the most revolutionary development in concrete construction for several decades. However, till this day SCC is only hesitantly accepted by concrete industry. The reasons are analyzed in this thesis. The presented design concept is a packing-based approach which considers entire particle size span of all solid ingredients from finest to coarsest particle. Using continuous geometric packing models, an optimization algorithm was developed, which allows, only by introduction of some basic material information, to perform a computer-based optimization which can be adapted to its practical needs with only a few experimental steps on mortar scale. Along with preparation of this new simplified design concept, powders, most important fraction of SCCs, were analyzed in detail. In particular relationship between grading (packing) and water demand were of interest. One of outcomes is a model about a constant water layer around any sized particle, which allows prediction of water demands and workability. A further advantage of mix design is replaceability of materials which allows for an optimization with locally available materials, one major request of industry. Moreover, alternative materials, preferably mineral waste materials can be added to mix this way. Due to improvement of packing notably less cement is needed to obtain a certain strength compared to conventionally designed SCCs and produced SCC possess a remarkable stability. This lowered cement content and possibility to introduce large amounts of waste materials notably improves ecological balance sheet of this new type of concrete. The outcome is a new type of SCC with superior workability and a possibly lower cost price than conventional concrete while having less impact on environment - a true-eco SCC. The ecological assessment is carried out using feasible models beyond carbon footprint which is typically referred to. In order to strengthen position of concrete as an ecological and sustainable construction material, two more aspects are investigated. This is use of encapsulated Phase-Change Materials (PCMs) and application of a self-cleaning and air-purifying effect on concrete surfaces. Both aspects comprise enormous potential and add new functions to construction material concrete, which by now is truly a high-tech building material.