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Verification of ECPC and EPCC concepts for the use of the k-value of selected active admixtures with mixed cement
Prudil, Matěj ; Slánský,, Bohuslav (referee) ; Hela, Rudolf (advisor)
This bachelor thesis deals with the verification of the replacement of blended cement, latent hydraulic and pozzolanic additions used in the production of concrete. In the theoretical part of this thesis, the use of blended cements in concrete production is firstly described and the effect of additions on the properties of fresh and hardened concrete is briefly discussed. The next chapters focus on fly ash and blast furnace slag as Type II additions and their basic properties. The theoretical part also focuses exclusively on the concepts used to replace cement with active additions. These concepts are successively presented in this thesis as: K-value concept, Equivalent concrete performance concept (ECPC) and Equivalent performance of combinations concept (EPCC). In the experimental part, the properties of the test mortars with cement replacement by concrete active additions (slag from Kotouč Štramberk and high temperature fly ash from Opatovice and Chvaletice) are compared. The above mentioned concepts for the replacement of cement with active additions are evaluated in the experimental part from the economic point of view (prices per m3 of concrete) and ecological point of view (calculation of carbon footprint in t CO2 per m3 of concrete production). In order to compare these benefits, a concrete mix of strength class C30/37 is proposed according to each concept. From the knowledge gained in the development of the ECPC and EPCC concepts, a q-value concept is proposed in the experimental part. In the last chapter of the experimental part, the resulting values of this work are compared with the experimental work already carried out to replace Portland cement with identical active admixtures.
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Mechanical activation of recycled concrete as an active ingredient
Opat, Lubomír ; Hela,, Vlastimil (referee) ; Hela, Rudolf (advisor)
This diploma thesis deals with the issue of using fine powder of concrete recyclate. In this thesis, the theoretical expectations of milling are summarized as well as high energy milling. Afterwards professional articles, in which fine powder of concrete recyclate is successfully activated, are described and commented on. In the experimental part, there are 11 recipes of cement mortar and 3 recipes of concrete mixed. The benefit of using fine powder of concrete recyclate as a possible substitute for part of the cement is evaluated.
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Study of possibilities of activation of power plant fly ash as an active ingredient in concrete
Máša, Jiří ; Uher, Vojtěch (referee) ; Hela, Rudolf (advisor)
Global concrete production is increasing, which brings some environmental burden. A certain solution is the use of secondary raw materials, which has been a long-standing practice in the construction industry. One of the most widespread secondary raw materials is power fly ash. However, in recent years trends have been directed towards maximizing their utility properties. The aim of this work was to study the possibilities of activation of power plant fly ash as an active admixture in concrete. The thesis is divided into two parts, the theoretical and the practical part. The theoretical part describes in detail the possibilities of power plant fly ash activation for use as an active admixture in concrete. The practical part of the thesis is focused on mechanical activation, where the knowledge of the theoretical part is verified on various fly ash.
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Study of the concept of K-value and efficiency index for fly ash and slag and their assessment and determination for concrete
Šperling, Petr ; Hela, Rudolf (referee) ; Hubáček, Adam (advisor)
This bachelor thesis deals with the use of active admixtures as a substitute for cement in concrete, specifically power plant fly ash and blast furnace slag. When using power plant fly ash and blast furnace slag as a substitute for cement in concrete, it is necessary to know their effect on concrete and to assess the different properties compared to concrete in which these admixtures are not used. This work will summarize the existing knowledge of the properties of power plant fly ash and blast furnace slag and their effect on fresh and hardened concrete. Furthermore, the possibilities of determining the efficiency index and the so-called k-value concept, which are used to assess the effect on cement mortar and concrete when replacing cement with an active admixture, will be summarized. In the experimental part, emphasis will be placed on determining the k-value. This is described in European technical standards in a very general way and is not sufficiently detailed for specific active ingredients.
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Optimizing the use of active admixtures in mixed cements and determining the k value
Kužílková, Hana ; Hubáček, Adam (referee) ; Hela, Rudolf (advisor)
The goal of this bachelor's thesis is to examine the possibility of using admixtures as a partial substitute for cement in concrete. The thesis examines the replacement of cement with three specific additives: micronized limestone, power plant fly ash and blast furnace slag. When using an admixture as a partial replacement for cement, the addition of the admixture affects the properties of both fresh and hardened concrete. The theoretical part of the work is devoted to the description of admixtures and their influence on the properties of fresh and hardened concrete. Furthermore, basic information on the efficiency index and k-value is presented. The aim of the practical part of the bachelor's thesis is to determine the efficiency indices of the given additives as well as their k-values.
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Mechanical activation of recycled concrete as an active ingredient
Opat, Lubomír ; Hela,, Vlastimil (referee) ; Hela, Rudolf (advisor)
This diploma thesis deals with the issue of using fine powder of concrete recyclate. In this thesis, the theoretical expectations of milling are summarized as well as high energy milling. Afterwards professional articles, in which fine powder of concrete recyclate is successfully activated, are described and commented on. In the experimental part, there are 11 recipes of cement mortar and 3 recipes of concrete mixed. The benefit of using fine powder of concrete recyclate as a possible substitute for part of the cement is evaluated.
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Study of possibilities of activation of power plant fly ash as an active ingredient in concrete
Máša, Jiří ; Uher, Vojtěch (referee) ; Hela, Rudolf (advisor)
Global concrete production is increasing, which brings some environmental burden. A certain solution is the use of secondary raw materials, which has been a long-standing practice in the construction industry. One of the most widespread secondary raw materials is power fly ash. However, in recent years trends have been directed towards maximizing their utility properties. The aim of this work was to study the possibilities of activation of power plant fly ash as an active admixture in concrete. The thesis is divided into two parts, the theoretical and the practical part. The theoretical part describes in detail the possibilities of power plant fly ash activation for use as an active admixture in concrete. The practical part of the thesis is focused on mechanical activation, where the knowledge of the theoretical part is verified on various fly ash.
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