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Pervious concrete is characterized by its open-void structure, which gives it a number of specific properties and allows specific applications, including pervious pavements, residential roads, alleys, sidewalks, parking lots, patios, and so on. Permeable areas are extremely important for the creation of sustainable cities in terms of the water cycle. Due to its high void content and low cement/mortar content, pervious concrete generally may have significantly reduced strength when compared with conventional concrete. That is why a wide range of research activities is devoted to the balance between acceptable void content, strength, as well as other significant properties. Knowledge of the relationships between the individual properties is very important for understanding this specific material. In this paper, a wide range of 38 different composition variants has been tested to determine the dependencies between the essential properties of pervious concrete. The variables related to the type of aggregate, maximum grain size, the grain-size composition, the amount of binder, and the kind (composition) of binder. The dependencies reported in the article are defined with high reliability R2 ranging from 0.75 to 0.95. On the basis of the dependencies thus determined, it can be predicted that a density of min. 1740 kg/m3 must be reached to meet the requirement of min. 10 MPa for nonpavement applications, while a density of min. 1960 kg/m3 must be achieved to meet min. 20 MPa for pavement applications. The criteria of the void ratio for pavement applications can be set at 20 ± 3%, while the criteria for nonpavement applications can be set at 28 ± 6%.
Alena Sičáková; Marek Kováč. Relationships between Functional Properties of Pervious Concrete. Sustainability 2020, 12, 6318 .
AMA StyleAlena Sičáková, Marek Kováč. Relationships between Functional Properties of Pervious Concrete. Sustainability. 2020; 12 (16):6318.
Chicago/Turabian StyleAlena Sičáková; Marek Kováč. 2020. "Relationships between Functional Properties of Pervious Concrete." Sustainability 12, no. 16: 6318.
This study compares the performance of perlite with that of conventional additives in blended cements. The results of the application of Perlite Powder (PP) as a component of blended cements in two different proportions (30% and 50%) are presented and compared with standard additives of fly ash (FA) and Ground Granulated Blast Furnace Slag (GGBFS). Moreover, perlite is tested as a component of ternary cement (70% cement, 15% P and 15% FA and GGBFS alternatively). Blended cements are tested in terms of flexural strength, compressive strength, bulk density, water absorption, and frost resistance. The results show that although perlite blended cements achieve lower strengths and higher absorptivity compared to conventional additives, they have significant potential for freezing and thawing durability, especially in ternary combination with GGBFS. For practical applications, the intrinsic values of the parameters of the individual binders with perlite (e.g. flexural strength of 4.1–6.2MPa or compressive strength of 18.8–38.5MPa) are sufficient for many practical applications. Perlite, when suitably combined with other pozzolanic materials, can be a suitable component of blended binders.
A. Sicakova; E. Kardosova; M. Spak. Perlite Application and Performance Comparison to Conventional Additives in Blended Cement. Engineering, Technology & Applied Science Research 2020, 10, 5613 -5618.
AMA StyleA. Sicakova, E. Kardosova, M. Spak. Perlite Application and Performance Comparison to Conventional Additives in Blended Cement. Engineering, Technology & Applied Science Research. 2020; 10 (3):5613-5618.
Chicago/Turabian StyleA. Sicakova; E. Kardosova; M. Spak. 2020. "Perlite Application and Performance Comparison to Conventional Additives in Blended Cement." Engineering, Technology & Applied Science Research 10, no. 3: 5613-5618.
Concretes in which a large portion of fine natural aggregate is replaced with inert mineral powders would offer both economic and ecological benefits for the concrete industry, and they represent eco-friendly materials. Moreover, using the powders having potential pozzolanic effect could have positive extra effect on the properties of concrete. This paper analyses the impact of a high dosage of three kinds of micro-fillers (brick, concrete and glass powders) on the properties of concrete over a three-year period. Microfillers were applied as 40% replacement of 0/4 aggregate by volume. Samples having high dosage of micro-fillers and thus a higher binder volume achieved excellent values of both compressive (from 31 to 48 MPa in 28 days, and from 67 to 93 MPa in three years) and flexural strength (from 6.3 to 8.4 MPa in 28 days, and from 7.1 to 11.1 MPa in three years). Both samples with brick powder and concrete powder achieved the biggest strength values; however, due to better performance in durability parameters (capillary water absorption coefficient and density), sample prepared with glass powder can be identified as having the biggest potential for intended use.
Alena Sičáková; Matej Špak. The Effect of a High Amount of Micro-Fillers on the Long-Term Properties of Concrete. Materials 2019, 12, 3421 .
AMA StyleAlena Sičáková, Matej Špak. The Effect of a High Amount of Micro-Fillers on the Long-Term Properties of Concrete. Materials. 2019; 12 (20):3421.
Chicago/Turabian StyleAlena Sičáková; Matej Špak. 2019. "The Effect of a High Amount of Micro-Fillers on the Long-Term Properties of Concrete." Materials 12, no. 20: 3421.
Concretes prepared by the application of the triple mixing approach and by the use of both recycled concrete aggregate (RCA) and recycled clay brick aggregate (RBA) were tested in terms of loss of consistency. Fly ash was used to improve the performance of recycled aggregates during mixing – this is a specific aspect of the triple-mixing method. The slump test was performed immediately after mixing, as well as after next 90 minutes. The results were evaluated from the point of view of prolonged discharge time. Concrete consistency changes with time, having the impact on technological processes at construction site. Over the discharge time, the RBA-based concrete achieved the worst result – by 87% slump loss. Discharge time influenced the slump loss more favourably in the case of normal mixing and in the case of using natural aggregate (NA). The substitution of NA with both the RCA and RBA caused the slump loss turned worse, while RCA provided better results than RBA. However, the substitution of NA with both RCA and RBA resulted in more favourable change in the slump loss when concrete was mixed by 3M method.
A Sicakova; K Urban. The impact of aggregates from recycling, discharge time and mixing technique on the consistency of concrete. IOP Conference Series: Materials Science and Engineering 2019, 549, 012002 .
AMA StyleA Sicakova, K Urban. The impact of aggregates from recycling, discharge time and mixing technique on the consistency of concrete. IOP Conference Series: Materials Science and Engineering. 2019; 549 (1):012002.
Chicago/Turabian StyleA Sicakova; K Urban. 2019. "The impact of aggregates from recycling, discharge time and mixing technique on the consistency of concrete." IOP Conference Series: Materials Science and Engineering 549, no. 1: 012002.
Compressive strength of concrete having recycled concrete aggregate is influenced by the properties and amount of those aggregate. The worse quality of RCA can be eliminated by specific mixing approach. Practical mixing and delivery of concrete could affect the properties of ready concrete due to prolonged time. In this paper, both the fly ash and fine fraction of recycled concrete were used to improve the quality of concrete due to coating of RCA, while the triple mixing technology was applied for this purpose. The compressive strength is evaluated from two aspects: the curing time (2, 28 and 90 days) and discharge time (0, 45 and 90 minutes after mixing) with attention being paid to the type of aggregate and the type of coating material. When using triple mixing technology, prolonged discharge time brings only small effect on the compressive strength (up to 12%) both in positive and negative way, depending on kind of coating material.
Karol Urban; Alena Sicakova. Analysis of compressive strength of concrete prepared by triplemixing technology depending on both the discharge and curing time. Selected Scientific Papers - Journal of Civil Engineering 2018, 13, 113 -121.
AMA StyleKarol Urban, Alena Sicakova. Analysis of compressive strength of concrete prepared by triplemixing technology depending on both the discharge and curing time. Selected Scientific Papers - Journal of Civil Engineering. 2018; 13 (1):113-121.
Chicago/Turabian StyleKarol Urban; Alena Sicakova. 2018. "Analysis of compressive strength of concrete prepared by triplemixing technology depending on both the discharge and curing time." Selected Scientific Papers - Journal of Civil Engineering 13, no. 1: 113-121.
The treatment of concrete surface using more durable material is one way to slow down the damage process of material, which can negatively affect durability of construction. This paper is aimed at testing the geopolymer-type coating materials of different composition while placing emphasis on various techniques of surface pre-treatments of concrete to which they were applied. The main composition variables were as follows: the fly ash fineness (original, ground) and the addition of washing-aggregate sludge. Four compositions were tested and compared with the composition based on cement binder. The cement mixture was prepared using the same fillers. The following techniques of surface pre-treatment of concrete were applied: brushing, pressure washing, and pressure washing followed by penetration, together with non-treated surface being used for comparison. The effect of the surface treatment technique was tested through the adhesion strength, which was executed at 2, 7, 28, and 120 days after application of the coating. The influence of the composition of geopolymer coating material was also discussed. Geopolymer-based mixtures achieved better adhesive strength than the cement-based mixture, regardless of surface treatment technique. The addition of sludge microfiller seems to be beneficial in improving the adhesive strength of geopolymer-type coating material.
Alena Sicakova. The Influence of Different Pre-Treatments of Concrete Surface on the Bond Strength of Geopolymer-Type Coating Layer. Sustainability 2018, 10, 4053 .
AMA StyleAlena Sicakova. The Influence of Different Pre-Treatments of Concrete Surface on the Bond Strength of Geopolymer-Type Coating Layer. Sustainability. 2018; 10 (11):4053.
Chicago/Turabian StyleAlena Sicakova. 2018. "The Influence of Different Pre-Treatments of Concrete Surface on the Bond Strength of Geopolymer-Type Coating Layer." Sustainability 10, no. 11: 4053.
Application of recycled aggregates (RA) for concrete production is limited due to their poor quality. While the environmental benefits of using the RA are well accepted, some unsolved problems prevent this type of material from wide application in structural concrete. The research and development of techniques which can minimize the adverse effect of RA on the concrete properties are highly requested. A specific mixing approach can also be helpful; here, mineral additives play a significant role for improvement of RA performance within the mixing process. However, delivery process can influence the homogeneity and uniformity of the concrete mixtures, resulting in negative effect on technical parameters. In this study, the impact of delivery time (0 min, 45 min, and 90 min) on the set of hardened concrete properties is presented while the three-stage mixing is used. Two kinds of additives—fly ash (FA) and recycled concrete powder (RCP)—were tested to coat the coarse fraction of recycled concrete aggregate (RCA) in the first step of mixing. For comparison, cement as coating material and natural aggregate instead the RCA were also used. The following parameters were tested after 28 days of setting and hardening: density, compressive strength, splitting tensile strength, water absorption capacity, and depth of penetration of water under pressure. Generally, 90 min of working with concrete mixtures left no significantly negative influence on tested characteristics. Based on ANOVA results, with prolonged discharge time, the changes in composition of the mixtures become less important for compressive strength, density, and water absorption.
Alena Sicakova; Karol Urban. The Influence of Discharge Time, Kind of Additive, and Kind of Aggregate on the Properties of Three-Stage Mixed Concrete. Sustainability 2018, 10, 3862 .
AMA StyleAlena Sicakova, Karol Urban. The Influence of Discharge Time, Kind of Additive, and Kind of Aggregate on the Properties of Three-Stage Mixed Concrete. Sustainability. 2018; 10 (11):3862.
Chicago/Turabian StyleAlena Sicakova; Karol Urban. 2018. "The Influence of Discharge Time, Kind of Additive, and Kind of Aggregate on the Properties of Three-Stage Mixed Concrete." Sustainability 10, no. 11: 3862.
Concrete is a dynamic material and its consistency changes with time, having impact on technological processes at working site. It is expressed due to slump loss - the reduction in slump from the time of original batching to the point when concrete is discharged from a truck mixer. Two kinds of additives (fly ash and recycled concrete powder) were tested to find their potential to improve the performance of recycled concrete aggregate in concrete, while the principle of triple-mixing method was adopted. Slump loss was evaluated based on measurements taken at 0, 45, and 90 minutes after mixing. The kind of aggregate, as well as kind of powdery material for coating the coarse fractions play significant role for the slump loss. Mixtures with fly ash as coating material achieved the biggest slump loss for both types of aggregate. The recycled concrete powder is well acceptable having similar impact on the slump loss as the cement has. When the NA is changed to RCA, the slump loss is higher and depends on material used for coating.
Alena Sičáková; Karol Urbán; Marek Kováč. Slump Loss of Concrete Based on RCA and Prepared by Specific Mixing Approach. Periodica Polytechnica Civil Engineering 2018, 1 .
AMA StyleAlena Sičáková, Karol Urbán, Marek Kováč. Slump Loss of Concrete Based on RCA and Prepared by Specific Mixing Approach. Periodica Polytechnica Civil Engineering. 2018; ():1.
Chicago/Turabian StyleAlena Sičáková; Karol Urbán; Marek Kováč. 2018. "Slump Loss of Concrete Based on RCA and Prepared by Specific Mixing Approach." Periodica Polytechnica Civil Engineering , no. : 1.
Alena Sicakova; Viola Hospodarova; Nadezda Stevulova; Vojtech Vaclavik. Effect of selected cellulosic fibers on the properties of cement based composites. Advanced Materials Letters 2018, 9, 606 -609.
AMA StyleAlena Sicakova, Viola Hospodarova, Nadezda Stevulova, Vojtech Vaclavik. Effect of selected cellulosic fibers on the properties of cement based composites. Advanced Materials Letters. 2018; 9 (8):606-609.
Chicago/Turabian StyleAlena Sicakova; Viola Hospodarova; Nadezda Stevulova; Vojtech Vaclavik. 2018. "Effect of selected cellulosic fibers on the properties of cement based composites." Advanced Materials Letters 9, no. 8: 606-609.
This experimental study was focused on the application of a surface-modified hemp- hurds aggregate into composites using an alternative binder of MgO-cement. This paper presents the results of the comparative study of the parameters (chemical and physico-chemical modification, and hardening time) affecting the physical (density, thermal conductivity coefficient and water-absorption behavior) and mechanical properties (compressive strength) of the bio-aggregate-based composite. A test of the parameters of the bio-composite samples showed some differences, which were determined by the chemical and surface properties of the modified filler, and which affected the mechanisms of hardening. The bulk density values of the hemp hurd composites hardened for 28 days place this material in the lightweight category of composites. The values of water absorption and the thermal conductivity coefficient of bio-composites decreased, and the strength parameter increased with an increase in the hardening time. The lower values of compressive strength, water absorption, and thermal conductivity coefficient (except for the ethylenediaminetetraacetic-acid-treated filler) were observed in composites based on fillers chemically treated with NaOH and Ca(OH)2) compared to referential composites (based on original hemp hurds). This is related to changes in the chemical composition of hemp hurds after chemical modification. The composites with ultrasound-treated hemp hurds had the greatest strengths at each hardening time. This is related to pulping the bundles of fibers and forming a larger surface area for bonding in the matrix.
Nadezda Stevulova; Julia Cigasova; Ivana Schwarzova; Alena Sicakova; Jozef Junak. Sustainable Bio-Aggregate-Based Composites Containing Hemp Hurds and Alternative Binder. Buildings 2018, 8, 25 .
AMA StyleNadezda Stevulova, Julia Cigasova, Ivana Schwarzova, Alena Sicakova, Jozef Junak. Sustainable Bio-Aggregate-Based Composites Containing Hemp Hurds and Alternative Binder. Buildings. 2018; 8 (2):25.
Chicago/Turabian StyleNadezda Stevulova; Julia Cigasova; Ivana Schwarzova; Alena Sicakova; Jozef Junak. 2018. "Sustainable Bio-Aggregate-Based Composites Containing Hemp Hurds and Alternative Binder." Buildings 8, no. 2: 25.
Pervious concrete is considered to be an advanced pavement material in terms of the environmental benefits arising from its basic feature—high water-permeability. This paper presents the results of experimental work that is aimed at testing technically important properties of pervious concrete prepared with three different water-to-cement ratios. The following properties of pervious concrete were tested—compressive and splitting tensile strength, unit weight at dry conditions, void content, and permeability. The mix proportions were expected to have the same volume of cement paste, and, to obtain the same 20% void content for all of the samples. The results show that changes of water-to-cement ratio from 0.35 to 0.25 caused only slight differences in strength characteristics. Arising tendency was found in the case of compressive strength and a decreasing tendency in the case of splitting tensile strength. The hydraulic conductivity ranged from 10.2 mm/s to 7.5 mm/s. The values of both the unit weight and void content were also analysed to compare the theoretical (calculated) values and real experiment results. A fairly good agreement was reached in the case of mixtures with 0.35 and 0.30 water-to-cement ratios, while minor differences were found in the case of 0.25 ratio. Finally, a very tight correlation was found between void content, hydraulic conductivity, and compressive strength.
Marek Kováč; Alena Sičáková. Pervious Concrete as an Environmental Solution for Pavements: Focus on Key Properties. Environments 2018, 5, 11 .
AMA StyleMarek Kováč, Alena Sičáková. Pervious Concrete as an Environmental Solution for Pavements: Focus on Key Properties. Environments. 2018; 5 (1):11.
Chicago/Turabian StyleMarek Kováč; Alena Sičáková. 2018. "Pervious Concrete as an Environmental Solution for Pavements: Focus on Key Properties." Environments 5, no. 1: 11.
The experiment aims to test the triple mixing (3M) technique to produce the concrete with recycled concrete aggregate (RCA). Then, the impact prolonged mixing, representing the influence of delivery and discharge time in praxis, is analysed by the change in strength properties. Both the 28-day compressive strength and tensile splitting strength are evaluated in two aspects: the prolonged mixing time (0, 45 and 90 min after initial mixing), and the mixing method (normal and triple). Prolonged mixing time brought both the positive and negative changes in strength characteristics however the worst difference between initial mixing (0′) and 90′ minutes of mixing was only 8.4% for compressive strength and 8.5% for tensile splitting strength.
Karol Urban; Alena Sicakova. The Effect of Mixing Technique and Prolonged Mixing Time on Strength Characteristics of Concrete. Proceedings 2018, 2, 1290 .
AMA StyleKarol Urban, Alena Sicakova. The Effect of Mixing Technique and Prolonged Mixing Time on Strength Characteristics of Concrete. Proceedings. 2018; 2 (20):1290.
Chicago/Turabian StyleKarol Urban; Alena Sicakova. 2018. "The Effect of Mixing Technique and Prolonged Mixing Time on Strength Characteristics of Concrete." Proceedings 2, no. 20: 1290.
The article deals with cement supplementary materials based on ground granulated blast furnace slag and zeolite. Purpose of the experiment was to observe dependences (if they exist) between selected parameters (modulus of basicity, modulus of hydraulicity and initial setting time) and activity indexes, for easier and quicker way to determine or predict the activity index. Testing showed that moderate dependences between those parameters and activity indexes were observed. Results showed that prediction of activity indexes based on chemical composition is feasible.
Marek Kovac; Alena Sicakova; Matej Spak. Testing the Supplementary Cementitious Material Based on GGBFS and Zeolite for Prediction of the Activity Index. Proceedings 2018, 2, 1287 .
AMA StyleMarek Kovac, Alena Sicakova, Matej Spak. Testing the Supplementary Cementitious Material Based on GGBFS and Zeolite for Prediction of the Activity Index. Proceedings. 2018; 2 (20):1287.
Chicago/Turabian StyleMarek Kovac; Alena Sicakova; Matej Spak. 2018. "Testing the Supplementary Cementitious Material Based on GGBFS and Zeolite for Prediction of the Activity Index." Proceedings 2, no. 20: 1287.
The experiment aims to test the specific way of producing concrete with recycled concrete aggregate (RCA). To reduce its negative impact on the concrete properties, two different ways of treatment of the RCA with geopolymer slurry were applied—coating during the mixing using the specific mixing approach and coating prior to the mixing of concrete. As control samples, a mixture prepared by natural aggregate only and a mixture with RCA that was prepared by standard mixing with no coating process were tested as well. The results of density, total water absorption, and compressive strength in periods of 28, 90, 180, and 365 days of curing are presented and evaluated. Both methods of coating of the RCA with geopolymer slurry allow for the preparation of concrete with properties comparable to those of normal concrete (prepared by standard mixing with natural aggregate); thus, it seems to be a promising way to enhance the rate of RCA application. The positive effect of coating is clearly visible after a longer period of curing (180 days). When comparing the methods of RCA coating, coating directly during the mixing yields somewhat better results; it is also positive from the technological point of view, since the process is simpler in practice.
Jozef Junak; Alena Sicakova. Effect of Surface Modifications of Recycled Concrete Aggregate on Concrete Properties. Buildings 2017, 8, 2 .
AMA StyleJozef Junak, Alena Sicakova. Effect of Surface Modifications of Recycled Concrete Aggregate on Concrete Properties. Buildings. 2017; 8 (1):2.
Chicago/Turabian StyleJozef Junak; Alena Sicakova. 2017. "Effect of Surface Modifications of Recycled Concrete Aggregate on Concrete Properties." Buildings 8, no. 1: 2.
This study is aimed at the utilization of natural zeolite as a prospective type of Supplementary Cementitious Material in connection with the innovations of construction solutions through the materials. The influence of zeolite on several properties of cement-based composites is studied. Basic characteristics of input powdery materials as well as the technological parameters of zeolite tested on mortar containing 50% of cement replacement are presented. The technical parameters of concrete containing 8, 13, and 25% of cement replacement by zeolite are presented as well. The paper is valuable due to the three-year testing period. The density of the hardened concrete was found to be decreasing with increasing zeolite content. While no significant differences in compressive strength were found after 28 days, differences between individual samples were clear after the long-term period. The presence of zeolite influenced the compressive strength positively in the case of the 8% and 13% replacement, while the higher proportion of natural zeolite (25%) caused lower compressive strength after 28 days but was similar to the reference concrete after three years. A major increase in strength was detected for all samples in the long-term period. It confirms the long-term potential of zeolite for strength improvement.
Alena Sičáková; Matej Špak; Mária Kozlovská; Marek Kováč. Long-Term Properties of Cement-Based Composites Incorporating Natural Zeolite as a Feature of Progressive Building Material. Advances in Materials Science and Engineering 2017, 2017, 1 -8.
AMA StyleAlena Sičáková, Matej Špak, Mária Kozlovská, Marek Kováč. Long-Term Properties of Cement-Based Composites Incorporating Natural Zeolite as a Feature of Progressive Building Material. Advances in Materials Science and Engineering. 2017; 2017 ():1-8.
Chicago/Turabian StyleAlena Sičáková; Matej Špak; Mária Kozlovská; Marek Kováč. 2017. "Long-Term Properties of Cement-Based Composites Incorporating Natural Zeolite as a Feature of Progressive Building Material." Advances in Materials Science and Engineering 2017, no. : 1-8.
The binding potential of fly ash (FA) as a typical basic component of building mixtures can be improved in mechanical way, which unfolds new possibilities of its utilization. This paper presents the possibilities of preparing the geopolymer mixtures based on ground (dm = 31.0 μm) FA, used in varying percentages to the original (unground; dm = 74.1 μm) one. As a modification, fine-grain sludge from the process of washing the crushed aggregates was used as filler in order to obtain mortar-type material. The basic physical-mechanical properties of mixtures are presented and discussed in the paper, focusing on time dependence. The following standard tests were executed after 2, 7, 28, and 120 days: density, total water absorption, flexural strength, and compressive strength. Ground FA provided for positive effect in all tested parameters, while incorporation of fine portion of sludge into the geopolymer mixture does not offer a significant technical profit. On the other hand, it does not cause the decline in the properties, so the environmental effect (reduction of environmental burden) can be applied through its incorporation into the geopolymer mixtures.
Alena Sičáková; Nadežda Števulová. Basic Physical – Mechanical Properties of Geopolymers Depending on the Content of Ground Fly Ash and Fines of Sludge. Selected Scientific Papers - Journal of Civil Engineering 2017, 12, 85 -96.
AMA StyleAlena Sičáková, Nadežda Števulová. Basic Physical – Mechanical Properties of Geopolymers Depending on the Content of Ground Fly Ash and Fines of Sludge. Selected Scientific Papers - Journal of Civil Engineering. 2017; 12 (1):85-96.
Chicago/Turabian StyleAlena Sičáková; Nadežda Števulová. 2017. "Basic Physical – Mechanical Properties of Geopolymers Depending on the Content of Ground Fly Ash and Fines of Sludge." Selected Scientific Papers - Journal of Civil Engineering 12, no. 1: 85-96.
Alena Sicakova; Martina Draganovska; Marek Kovac. Water Absorption Coefficient as a Performance Characteristic of Building Mixes Containing Fine Particles of Selected Recycled Materials. Procedia Engineering 2017, 180, 1256 -1265.
AMA StyleAlena Sicakova, Martina Draganovska, Marek Kovac. Water Absorption Coefficient as a Performance Characteristic of Building Mixes Containing Fine Particles of Selected Recycled Materials. Procedia Engineering. 2017; 180 ():1256-1265.
Chicago/Turabian StyleAlena Sicakova; Martina Draganovska; Marek Kovac. 2017. "Water Absorption Coefficient as a Performance Characteristic of Building Mixes Containing Fine Particles of Selected Recycled Materials." Procedia Engineering 180, no. : 1256-1265.
High water absorption of recycled brick aggregate (RBA) is one of the most discussed parameters in terms of its application in the production of concrete—its influence on the amount of mixing water and, hence, the quality of the concrete, is usually considered negative. In this paper, different methods of decreasing the absorption of RBA and, consequently, the impact on the properties of concrete, are described. The RBA has been treated to decrease the water absorption capacity by impregnation approach using specific impregnators. Afterwards, the RBA samples have been dried at two different temperatures in the laboratory oven—20 and 90 °C. Concretes using 4/8 fraction of the treated RBA instead of natural aggregate (NA) have been mixed and tested. The effectiveness of the RBA treatments have been evaluated on the basis of their influence on the properties of the hardened concrete; by means of the following tests: flexural strength, compressive strength, capillarity, total water absorption capacity, depth of water penetration under pressure, and frost resistance. The method of ranking by ordinal scale has been used as it is suitable for the comparison of a large set of results, while results have been analyzed in terms of the most important technological parameter that influences the quality of the concrete-effective water content. Out of all the tested surface-treatments of RBA, treatment by sodium water glass has the best potential for reduction of the water/cement (w/c) ratio. When the effective w/c ratio is kept within standard limits, concretes containing treated RBA are possible to be specified for various exposure classes and manufacturing in practice. The experiment confirms that at a constant amount of mixing water, with decreasing water absorption of RBA, the effective amount of water in the concrete increases and, hence, the final properties of the concrete decrease (get worse). As the water absorption of the RBA declines, there is a potential for the reduction of the w/c ratio and improvement in the quality of the concrete.
Marcela Ondova; Alena Sicakova. Evaluation of the Influence of Specific Surface Treatments of RBA on a Set of Properties of Concrete. Materials 2016, 9, 156 .
AMA StyleMarcela Ondova, Alena Sicakova. Evaluation of the Influence of Specific Surface Treatments of RBA on a Set of Properties of Concrete. Materials. 2016; 9 (3):156.
Chicago/Turabian StyleMarcela Ondova; Alena Sicakova. 2016. "Evaluation of the Influence of Specific Surface Treatments of RBA on a Set of Properties of Concrete." Materials 9, no. 3: 156.
Julia Cigasova; Nadezda Stevulova; Alena Sicakova. New biocomposites based on hemp hurds. Journal of Civil Engineering, Environment and Architecture 2015, XXXII, 75 -81.
AMA StyleJulia Cigasova, Nadezda Stevulova, Alena Sicakova. New biocomposites based on hemp hurds. Journal of Civil Engineering, Environment and Architecture. 2015; XXXII (3/II/2015):75-81.
Chicago/Turabian StyleJulia Cigasova; Nadezda Stevulova; Alena Sicakova. 2015. "New biocomposites based on hemp hurds." Journal of Civil Engineering, Environment and Architecture XXXII, no. 3/II/2015: 75-81.
Waste valorisation in production of building materials can be improved by their modification using some treatment technologies. Subsequently, products prepared using these optimized raw materials can show better or even new properties. Utilisation of construction and demolition waste (C&DW) for production of building materials is discussed for a longer time world-wide, whether in the form of coarse aggregates or in the fine-grain form as a micro-filler or as a binder. Both of these forms show specific problems have to be solved for increasing the quantities consumed. Fine-grain form can be obtained by techniques like crushing, grinding and sorting as well as by their combinations.This article is aimed on the utilization of specific portion of fine-grain C&DW (ceramics, glass and concrete) for production of concrete mixes of higher fluidity. C&DW were modified by specific process (defined method of crushing followed by sorting of particles under 250 μm). This material was expected as a micro-filler - substitution of natural aggregate (NA) in 0/4 fraction to the extent possible, that the rules allow. Using relevant calculations, 40% dosage was found as complying with standard limit for the maximum content (600 kg.m-3) of particles of less than 250 μm in whole mixture including the relative share of cement and NA. In accordance with these limiting factors, standard recipes were designed. Amount of water, as well as dosage of plasticizer was adjusted during mixing in order to keep the water/cement ratio (max. 0.6) and flow class F5 – F6.Resulting water consumption and dosage of plasticizer are discussed in the terms of influence of tested C&DW on the consistency and bleeding of concrete. Generally positive effect of fine-grain form of brick, glass and concrete was found compared to the reference concrete not containing those additive fine particles.
Alena Sicakova; Karol Urban; Martina Draganovska. Influence of High Dosage of Specific C&DW Micro-Fillers on the Fluidity of Concrete. Solid State Phenomena 2015, 244, 71 -76.
AMA StyleAlena Sicakova, Karol Urban, Martina Draganovska. Influence of High Dosage of Specific C&DW Micro-Fillers on the Fluidity of Concrete. Solid State Phenomena. 2015; 244 ():71-76.
Chicago/Turabian StyleAlena Sicakova; Karol Urban; Martina Draganovska. 2015. "Influence of High Dosage of Specific C&DW Micro-Fillers on the Fluidity of Concrete." Solid State Phenomena 244, no. : 71-76.