Periodic Reporting for period 2 - GeoDust (Utilization of secondary raw material in geopolymers production)
Okres sprawozdawczy: 2019-01-01 do 2022-03-31
Portland cement production consumes a lot of energy, natural resources and produces large amounts of greenhouse gases and waste in form of so-called cement kiln bypass dust (CBPD). Therefore, the utilization of CBPD together with other industrial wastes or by-products in the building industry would be more sustainable thanks to the utilization of the wastes as well as thanks to the reduction in the demand for Portland cement. A solution can be alkali-activated materials which have many other advantages such as durability or resistance to elevated temperatures. However, they have also some drawbacks, particularly extensive shrinkage, related cracking tendency and often fast setting time. In addition, before our project started, comprehensive research focused on the utilization of CBPD in alkali-activated materials was not conducted.
Objective of GeoDust project was to contribute to the common 2050 goal of reducing global CO2 emmision by 80%. Concrete, the most widely used construction material, whose production has serious environmental impacts due to high energy demands, the consumption of raw materials and greenhouse gasses, needs a search for a greener alternative. We developed cementless concretes based on industrial by-products or even wastes, and thus can save natural resources, energy and reduce emissions of greenhouse gases.
Exchange of knowledge and experience between academia and industry (production and R&I) creates a much better understanding of each working environment, which is highly beneficial for mutual cooperation. In our specific case, close cooperation was established between academia and the cement plant and expanded even far beyond the original scope of the project to improve the quality of ordinary cement and concretes and thus improve living standards.
The overall objectives of this project were to establish a strong partnership between scientific and industrial institutions across the EU.
To monitor the composition of CBPD over time and investigate their role in alkali-activated systems.
To develop non-traditional concrete based on industrial by-products and wastes, particularly cement bypass dust (CBPD) and blast furnace slag, and thus contribute to the sustainability of the building industry.
Comprehensive testing of alkali-activated concretes.
Knowledge sharing, training staff of the involved partners, and thus increae their competitiveness on the national and international level.
Objective of GeoDust project was to contribute to the common 2050 goal of reducing global CO2 emmision by 80%. Concrete, the most widely used construction material, whose production has serious environmental impacts due to high energy demands, the consumption of raw materials and greenhouse gasses, needs a search for a greener alternative. We developed cementless concretes based on industrial by-products or even wastes, and thus can save natural resources, energy and reduce emissions of greenhouse gases.
Exchange of knowledge and experience between academia and industry (production and R&I) creates a much better understanding of each working environment, which is highly beneficial for mutual cooperation. In our specific case, close cooperation was established between academia and the cement plant and expanded even far beyond the original scope of the project to improve the quality of ordinary cement and concretes and thus improve living standards.
The overall objectives of this project were to establish a strong partnership between scientific and industrial institutions across the EU.
To monitor the composition of CBPD over time and investigate their role in alkali-activated systems.
To develop non-traditional concrete based on industrial by-products and wastes, particularly cement bypass dust (CBPD) and blast furnace slag, and thus contribute to the sustainability of the building industry.
Comprehensive testing of alkali-activated concretes.
Knowledge sharing, training staff of the involved partners, and thus increae their competitiveness on the national and international level.
During the first months of project implementation, consortium members met each other and discussed the details of the work, secondments, data sharing and other necessities for smooth running of the project.
In the first year, the work carried out within the project was mainly focused on the characterization of the raw materials with special attention to CBPD, which is a waste from Portland cement manufacturing and has only very limited possibilities of utilization. The main goal was to find the best set of methods needed for the determination of the chemical and mineralogical composition of CBPD, as well as its physical properties, such as the particle size distribution. Knowledge of CBPD characteristics is essential for a reasonable development of any new system for its usage and helped us to proceed successfully during the following project stages.
Second and very wide task was development of a new type of cementless concrete, which contains CBPD and which will be usable instead of concretes based on Portland cement in some applications. At the same time, its preparation should be as simple and as cheap as possible, which relates to our efforts to use secondary raw materials as much as possible. Our concretes were based on alkali-activated blast furnace slag (AAS)-based binders, whose advantage is that they do not need curing at elevated temperatures. Unlike Portland cement, which hardens in the presence of a suitable amount of water, AAS also requires the presence of an alkaline activator (e.g. alkaline hydroxides, waterglass, etc.), which ensures the dissolution of slag particles to species that can build up a new solid structure with binding ability. Fresh and hardened properties of the prepared AAS-based materials depend on many factors and their combinations, where nature and dose of the alkaline activator and composition and dose of CBPD play crucial roles. Therefore, the effects of these and other factors were investigated in terms of consistency (how the material flows), setting time (period from mixing until the material is no longer workable), sufficient early and long-term strength, durability in various conditions, etc. Volume stability and tendency to surface cracking were also important aspects, as these belong to the most serious obstacles for wider utilization of AAS in practice.
This, was a real challenge, because by improving one parameter, another two were impaired. So, it was necessary to find a certain balance among all the desired aspects, without one significantly problematic. After optimization, we had to transfer our laboratory product to practice and verify its usability under conditions of larger scale of a concrete plant. Pilot production tests were successful and resulted in the production of various prefabricated products, such as concrete elements for railway marking or crash barriers. Along with these elements, many testing specimens were prepared to continue the testing of durability, strength, etc. Considerable attention was paid to the monitoring of the quality of the surface of our concretes, which resulted in further optimization and performance verification, during the pilot production tests. The advantage of developed concretes is that they can be produced using the devices and equipment commonly available in concrete plant.
It can be summarized that the project covered a wide range of scientific fields, from basic research with the participation of sophisticated instrumental techniques, to laboratory experiments with the pilot product produced on a large scale of concreting plants.
In the first year, the work carried out within the project was mainly focused on the characterization of the raw materials with special attention to CBPD, which is a waste from Portland cement manufacturing and has only very limited possibilities of utilization. The main goal was to find the best set of methods needed for the determination of the chemical and mineralogical composition of CBPD, as well as its physical properties, such as the particle size distribution. Knowledge of CBPD characteristics is essential for a reasonable development of any new system for its usage and helped us to proceed successfully during the following project stages.
Second and very wide task was development of a new type of cementless concrete, which contains CBPD and which will be usable instead of concretes based on Portland cement in some applications. At the same time, its preparation should be as simple and as cheap as possible, which relates to our efforts to use secondary raw materials as much as possible. Our concretes were based on alkali-activated blast furnace slag (AAS)-based binders, whose advantage is that they do not need curing at elevated temperatures. Unlike Portland cement, which hardens in the presence of a suitable amount of water, AAS also requires the presence of an alkaline activator (e.g. alkaline hydroxides, waterglass, etc.), which ensures the dissolution of slag particles to species that can build up a new solid structure with binding ability. Fresh and hardened properties of the prepared AAS-based materials depend on many factors and their combinations, where nature and dose of the alkaline activator and composition and dose of CBPD play crucial roles. Therefore, the effects of these and other factors were investigated in terms of consistency (how the material flows), setting time (period from mixing until the material is no longer workable), sufficient early and long-term strength, durability in various conditions, etc. Volume stability and tendency to surface cracking were also important aspects, as these belong to the most serious obstacles for wider utilization of AAS in practice.
This, was a real challenge, because by improving one parameter, another two were impaired. So, it was necessary to find a certain balance among all the desired aspects, without one significantly problematic. After optimization, we had to transfer our laboratory product to practice and verify its usability under conditions of larger scale of a concrete plant. Pilot production tests were successful and resulted in the production of various prefabricated products, such as concrete elements for railway marking or crash barriers. Along with these elements, many testing specimens were prepared to continue the testing of durability, strength, etc. Considerable attention was paid to the monitoring of the quality of the surface of our concretes, which resulted in further optimization and performance verification, during the pilot production tests. The advantage of developed concretes is that they can be produced using the devices and equipment commonly available in concrete plant.
It can be summarized that the project covered a wide range of scientific fields, from basic research with the participation of sophisticated instrumental techniques, to laboratory experiments with the pilot product produced on a large scale of concreting plants.
In this research field, there was almost no information on the role of CBPD in AAS before the project started. Therefore, it was exciting to pioneer this topic and significantly deepen the general knowledge. These included mainly the role of CBPD and its constituents in the reaction process of AAS, including the formation of reaction products in various environments. These aspects, often obtained using advanced instrumental techniques, were correlated and discussed with the macroscopically observed behaviour during the setting, hardening, and ageing of pastes, mortars, and concretes.
Many of these findings have been already published, while the publication of many others is still waiting for the end of long-term experiments planned over a time frame of several years and thus exceeding the project implementation itself. This mainly concerns the long-term performance of concretes placed in real outdoor conditions, which is very valuable and only scarcely published. Although the project was formally ended, it is still continuing thanks to these long-term experiments and thanks to the established cooperation as well.
For example, we are now working on improving of the compatibility of cement and organic additives, which is necessary for adequate performance of the concretes produced. This helps to produce concrete with the appropriate quality, without the need for repairs and related impact on the environment.
Many of these findings have been already published, while the publication of many others is still waiting for the end of long-term experiments planned over a time frame of several years and thus exceeding the project implementation itself. This mainly concerns the long-term performance of concretes placed in real outdoor conditions, which is very valuable and only scarcely published. Although the project was formally ended, it is still continuing thanks to these long-term experiments and thanks to the established cooperation as well.
For example, we are now working on improving of the compatibility of cement and organic additives, which is necessary for adequate performance of the concretes produced. This helps to produce concrete with the appropriate quality, without the need for repairs and related impact on the environment.