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NEW ECONOMICAL AND ECOLOGICAL SOLUTIONS TO REDUCE RAW MATERIAL COSTS OF CEMENT BASED PRODUCTS BY UTILIZING MICRO TECHNOLOGY

Final Report Summary - MICROCON (New economical and ecological solutions to reduce raw material costs of cement based products by utilising micro technology)

The project aimed to develop an economical and ecological cutting of the raw material costs of cementitious products by development of micro-filler-based composite for the concrete industry and at the same time providing an economical and ecological improvements in the technical properties of cementitious products. Raw material and production costs of cementitious products have increased and are increasing all the time. Simultaneously, as structures of tomorrow become larger and more complex, the materials of construction will be required to meet more demanding standards of performance than those in force today. High performance concrete should have properties such as high workability, dimensional stability, and strength, and long durability in service. This trend has led to the use of higher cement contents and more admixtures in cementitious products. This concerns especially products like self compacting concrete (SCC).

Microstructure of concrete and mortars has a great impact on the properties of fresh and hardened concrete. The project sought to improve these properties through development of waste based filler composites, which could help to optimise microstructure of cementitious products and reduce the need for high cement and admixture amounts.

The optimised micro-composite is a potential commercial product for the manufacture of high performance mortars and concretes (ready mixed concretes, precast concrete products including SCC and dry pre-mix products), and has the potential of improving the competitiveness of companies by reducing their raw material costs and of increasing their turnover either as end-users or as producers of micro-filler composites or both.

More information available on the project website http://www.microcon.us.

During the mix design process of the project, focus was placed on product development of micro-filler composites and related product applications. It included optimisation of mix designs and analysis influence of microcomposites in the products. Mix design phase started with series of tests with microcomposite samples of two producers. The work consisted of studies with varying amounts and types of microfillers in different chosen product applications. These studies were both theoretical and practical including tests with fresh and hardened products. The tests were made according to the valid or preliminary EN standards. The studies included identification of usability limits for micro-composites with varying mix designs. The tests included durability and long-term ageing tests especially relating to microstructures of the products. Already the first tests with ultra fine micronised fly ash pointed out that the cement replacement of 30-50 kg/m3 of micronised fly ash improved performance of fresh concrete and long-term performance. The results of the tests with SCC showed that with microsomposite you can improve properties of fresh concrete, robustness, long term strength and durability (microcracks). Tests with brick tile mortar showed that microcomposite can improve compressive strength of mortars. Series of tests with cement based rock grouts proved that microcement can be replaced up to 80 % with micronised industrial by-product or recycled material still achieving excellent workability properties, strength development and final strength.

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