Mogućnost primene industrijskih nusproizvoda u geopolimernim malterima i betonima na bazi elektrofilterskog pepela

The connection between eco and building materials can be successfully accomplished by using geopolymers. Geopolymers are composite materials made of long chain molecules incurred by polymerization of geopolymer binders. Usually, geopolymers are defined as a solid and stabile aluminosilicate materials, made of industrial byproducts and liquid solutions such as NaOH and Na2SiO2. …The experimental part of the dissertation, contains the results of physical-mechanical, microscopic and durability properties of geopolymer mortars and concrete based on fly ash. For the purpose of determining the effect of different byproducts on characteristics of geopolymer mixtures, 24 batches of mortar and 8 batches of concrete were made and tested. Mass percentages of ladle slag, wood ash, red mud and waste glass in respect to the total mass of the binder was 0 to 20%, varied in 5 % steps of replacement. Mass percentage of ground granulated blast furnace slag in respect to the total mass of the binder was 0 to 100%, varied in steps of 20 % steps of replacement. All batches were made by using binder with the particle size smaller than 0,09 mm. The samples of geopolymer mortar and concrete were cured at an ambient temperature. …According to the test results some recommendations for the possible application of fly ash and other industrial byproducts for making geopolymer mortars and concretes are made. It has been proved that geopolymer mortars and concretes might be used as a construction building materials. Furthermore, because of their physical-mechanical characteristics and durability properties, they can be alternative solution for the traditional mortar and concrete mixtures

Possibilities of Biomass Wood Ash Usage in Geopolymer Mixtures

This paper presents the results of testing the physical and mechanical properties and durability of geopolymer mixtures. Fly ash was used as the basic binder, while its replacement was performed with wood biomass ash.The initial and final setting time were tested on the geopolymer paste, while flow value and bulk density were tested on the fresh mortar. Compressive and flexural strength and sulfate and freeze-thaw resistance were tested on hardened geopolymer mortar. Based on the most optimal results of mortar testing, the composition of concrete was determined, and slump, bulk density, compressive and flexural strength, penetration of water under pressure and sulfate and freeze-thaw resistance were tested. According to the results of compressive strength tests of geopolymer materials and concrete exposed to sulfate solution attack, the mixtures prepared with the addition of 20% wood biomass ash showed better sulfate resistance than the mixtures prepared only with fly ash

HIGH STRENGTH CONCRETES BASED ON THE CHOICE OF THE BEST PARTICLE SIZE DISTRIBUTION IN AGGREGATE

The requirements of the modern (high-end) construction industry demand the development of new types of concrete of high, and especially very high strength and with significantly improved properties in terms of durability. They provide new possibilities in the field of concrete technology of high strength and performance. When designing the composition of high-strength concrete (HSC), a special attention should be paid to the particle size distribution of aggregates, which should be chosen so as to achieve an "optimal" packing of the aggregate grains. The maximum grain size has been reduced to 2 mm. The Funk-Dinger formula was used to calculate the particle size distribution, which also takes into account fine particles of mineral powder additives. CEM I 52.5R, pure quartz sand, quartz filler, silica fume, powerful superplasticizer and low water/binder ratio were chosen for making HSC. In total, five different concrete mixtures were made. The paper presents the results of testing important properties of hardened concrete at ages from 1 day to 90 days and statistical processing of the obtained test results

Concrete Resistance Achieved with Subtly Ground Tube Glass of Cathode Ray as Supplementary Cementitious Material to Sulphate Attack

One of the essential requirements in modern civil engineering is a sustainable building, with the aim of reducing the harmful impact on the environment. Since the early XXI century, usage of recycled materials has been insisted on, which could, at least partly, substitute traditionally used materials. Although there is no serial manufacturing of TV sets with cathode ray tubes anymore, piles of cathode ray tube glass (CRT) at the waste disposal sites have still been on the increase. This experimental research was supposed to determine the potential for using subtly milled CRT glass as a supplementary cementitious material and to check the resistance of similar concretes to the sulphate action. Six testing concrete batches were made. The percentage of cement replacement percentage with CRT was: 5%, 10%, 15%, 20% and 35%, by mass. Durability assessment of concrete to sulphate action was done by visual estimation of concrete appearance as well as through testing the compressive strength variations of treated concrete specimens 3, 6, 12 and 36 months old. After soaking the specimens in a 5% solution of Na2SO4 for 36 months, concretes with 15% to 20% of replaced cement with finely ground CRT glass have simultaneously satisfactory compressive strength and resistance to sulfate attack. In this sense, this range of replacement of cement with finely ground CRT glass can be recommended for practical application

Gaussian Regression Process for Prediction of Compressive Strength of Thermally Activated Geopolymer Mortars

The primary objective of this research is the development of a prediction model of the compressive strength of geopolymer mortars made with fly ash and granular slag which hardened in different curing conditions. Data for the numerical analysis were obtained by experimental research; for this purpose 45 series of geopolymer mortars were made, 9 of which were cured in ambient conditions at a temperature of 22 °С, and the remaining were exposed to thermal activation for a duration of 24 h at the temperatures of 65 °С, 75 °С, 85 °С and 95 °С. Using machine learning, a Gaussian regression method was developed in which the curing temperature and the percentage mass content of fly ash and granular slag were used as input parameters, and the compressive strength as the output. Based on the results of the developed model, it can be concluded that the Gaussian regression process can be used as a reliable regression method for predicting the compressive strength of geopolymer mortars based on fly ash and granular slag

Application of industrial by-products as mineral admixtures for self-compacting concrete

Upotreba otpadnih materijala kao mineralnih dodataka samozbijajućem betonu može pridonijeti rješavanju problema njihovog odlaganja, ali je potrebno utvrditi njihovu djelotvornost. Ispitan utjecaj elektrofiltarskog pepela, mljevenih otpadnih opekarskih elemenata – crjepova, flotacijske jalovine i silicijske prašine na konzistenciju betona i njihove tlačne čvrstoće, vlačnu čvrstoću pri savijanju i vlačnu čvrstoću pri cijepanju. Dobiveni rezultati ispitivanja mješavina samozbijajućeg betona su uspoređeni s mješavinom konvencionalnog betona.Although the use of waste materials as mineral admixtures for self-compacting concrete can contribute to solving the problem of their disposal, the effect of such use should be further explored. The influence of fly ash, powdered waste brick elements - roof tiles, flotation tailing and silica fume, on the consistency, compressive strength, bending tensile strength, and tensile splitting strength of concrete, is studied. Self-compacting concrete mixtures test results are compared to a common concrete mixture