scholarly journals Self-Compacting Concrete and Concreting Technology for Foundation Block Using 9000 Cubic Meters of Concrete

2021 ◽  
Vol 20 (4) ◽  
pp. 329-337
Author(s):  
E. I. Batyanovskiy ◽  
A. I. Bondarovich ◽  
N. N. Kalinovskaya ◽  
P. V. Ryabchikov
Keyword(s):  
Mechanical Properties ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
Test Methods ◽  
Third Party ◽  
Hardened Concrete ◽  
Self Compacting Concrete ◽  
Foundation Slab ◽  
Concrete Mixtures ◽  
Structure Height

. The paper presents the results of the development and implementation of the technology of self-compacting heavy structural concrete and the technology of concreting with its use of the largest foundation slab in Belarus (concrete volume ~9100 m3) of a high-rise building at the facility “Construction of a multifunctional complex in Minsk within the boundaries of Filimonova Street – Avenue Nezavisimosty – Makayonka Street”. The results of research are shown, which ensured the production of self-compacting concrete of class C35/45 with water resistance up to W20 (with the required W12 according to the project) from concrete mixtures of the maximum cone expansion of the PK6 (RK6) grade for three zones of the foundation slab different in degree of reinforcement: lower, middle and upper, with a total structure height of 3.5 m and plan dimensions ~(83´34) m. The technology of continuous (seamless) concreting has been developed and implemented, which made it possible to lay ~9100 m3 of concrete into the structure without defects within 42 hours of continuous operation, and a system of technological measures that prevented temperature cracking in concrete. The homogeneity of the physical and mechanical properties of concrete, confirmed by control tests, is ensured due to the uniform supply of the concrete mixture (from six  concrete pumps at the same time) in layers 200–300 mm high with a distance between the supply points of about 5–6 m and the vertical arrangement of the “trunks” of the concrete pipes during delivery of concrete to each point, as well as the fact that the time for feeding the next volume of concrete was significantly less than the setting time of the previously laid concrete (with a total concreting speed £0.1 m/h). Standardized and original test methods for concrete mixtures, hardening kinetics and properties of hardened concrete have been used during the development, research and implementation of the project. Control tests of physical and mechanical properties and characteristics of concrete, carried out at BNTU together with authorized  organizations controlling the progress of construction, as well as in independent (third-party) organizations, have confirmed their compliance with the design requirements.

The Behavior of FRA Concrete with High Replacement Ratio

2018 ◽  
Vol 760 ◽  
pp. 204-209 ◽  
Author(s):  
Magdaléna Šefflová
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Absorption Capacity ◽  
Recycled Aggregate ◽  
Partial Replacement ◽  
Hardened Concrete ◽  
Replacement Ratio ◽  
Natural Sand ◽  
Concrete Mixtures

This study deals with determination of the properties of the fine recycled aggregate (FRA) concrete with partial replacement of natural sand in concrete mixtures. The FRA was obtained from concrete waste and crushed on fraction 0 – 4 mm by laboratory jaw crusher. The geometrical and physical properties of natural sand and the FRA were tested. The main goal of this study is evaluation of the basic physical and mechanical properties of the concrete with partial natural sand replacement by the FRA such as workability, water absorption capacity, compressive strength and flexural strength. A total four concrete mixtures were prepared. The first concrete mixture was prepared only with natural sand, did not include the FRA. In other concrete mixtures, natural sand was replaced by the FRA in various replacement ratios (40 %, 50 %, and 60 %). All concrete mixtures were designated with the same parameters for clear comparison. The workability of fresh concrete mixtures and physical and mechanical properties of hardened concrete were tested.

scholarly journals KUAT TEKAN BETON CAMPURAN GGBFS DAN FLY ASH MENGGUNAKAN RETARDER

2021 ◽  
Vol 15 (1) ◽  
pp. 51
Author(s):  
Anni Susilowati ◽  
Iqbal Yusra
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
Test Methods ◽  
Optimum Level ◽  
Statistical Regression ◽  
Level Of Use ◽  
Regression Test

Abstract One of the world's construction needs is casting in large volumes that require concrete with low hydration heat, and one of the problems is that the concrete has a setting during the casting queue. Therefore, a research was conducted on adding retarder to concrete with a mixture of GGBFS and Fly Ash. The purpose of this research was to analyze the physical and mechanical properties of concrete, the effect of adding retarder and obtain optimal retarder levels. This research used an experimental methods to make concrete specimens of 75% cement mix: GGBFS 15%: Fly Ash 10% with a water cement ratio of 0.5 using mix design SNI-03-2834-2000. Variations of the retarder added to the concrete mixture were 0%, 0.2%, 0.4%, and 0.6% by weight of cement with the Naptha RD 31 type. Analysis of the effect of the retarder used statistical regression test methods on SPSS. The results of research obtained the longest setting time in this researchwas 1890 minutes at a variation of 0.6% with a slump of 168 mm. The compressive strength of the concrete increased by 12.07% - 52.36% by using a retarder added material. Based on the research results, it was obtained that the optimum level of use of retarder in mixed concrete GGBFS and Fly Ash was 0.2% because it has the best physical and mechanical properties. Keywords: Fly Ash, GGBFS, Compressive Strength, Retarder

scholarly journals To the problem of forming the high-strength concrete dispersed composition and properties

Vestnik MGSU ◽  
2020 ◽  
pp. 235-243
Author(s):  
Evgeniy G. Velichko ◽  
Yuliya S. Shumilina
Keyword(s):  
Mechanical Properties ◽  
High Strength Concrete ◽  
Physical And Mechanical Properties ◽  
High Strength ◽  
Self Compacting Concrete ◽  
Strength Concrete ◽  
Concrete Mixtures ◽  
Multi Level ◽  
High Valent ◽  
Structural Levels

Introduction. Significant disadvantages of currently used high-strength concrete are the high absolute consumption of binder as well as its low specific consumption per unit of strength. Including many components with the goal of multi-level optimization of the dispersed composition is one of the main methods for producing high-strength concretes with a minimum content of cement and high physical and mechanical properties. Obtaining such concretes can be connected with creating a dense high-aggregated solid phase of the constituents at various structural levels and low water-to-cement ratio. Materials and methods. he following components were used to study the properties and structure of the concrete: two fine aggregate fractions, granite-gabbro crushed stone of 5 to 10 mm fraction, portland cement of the CEM I 42.5N class, finely dispersed blast furnace granulated slag, metakaolin, silica fume, high-dispersed cement fraction, Glenium 430 superplasticizer, and high-valent hardening accelerator. The shape and size of the dispersed particles of the components were determined using a laser analyzer, the flowability of the concrete mixture was evaluated as per GOST 10181-2014 standard, while the concrete compressive strength following GOST 10180-2012 standard. The cement stone structure was studied using derivatographic analysis and x-ray phase analysis methods. Results. For concrete with an optimized dispersed composition, superplasticizer and high-valent hardening accelerator prepared using self-compacting concrete mixtures, the concrete strength at the age of 1 day after hardening was of 58,67 and 77 MPa and at the age of 28 days after hardening was of 150, 186 and 219 MPa under normal conditions and with cement consumption of 650, 710 and 770 kg/m3, respectively. Conclusions. Multi-level dispersion and granulometric modification in combination with chemical modification of the composition of self-compacting concrete mixtures is one of the most productive directions of research and synthesis of high-strength concrete with minimum consumption of Portland cement and high physical and mechanical properties. It is advisable to use several structural levels of the clinker component particles.

scholarly journals Effect of TiO2 Nanoparticles on Physical and Mechanical Properties of Cement at Low Temperatures

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Li Wang ◽  
Hongliang Zhang ◽  
Yang Gao
Keyword(s):  
Mechanical Properties ◽  
Low Temperatures ◽  
Cement Hydration ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
Xrd Analysis ◽  
Cementitious Materials ◽  
Strength Test ◽  
Hydration Degree ◽  
Time Test

Low temperature negatively affects the engineering performance of cementitious materials and hinders the construction productivity. Previous studies have already demonstrated that TiO2 nanoparticles can accelerate cement hydration and enhance the strength development of cementitious materials at room temperature. However, the performance of cementitious materials containing TiO2 nanoparticles at low temperatures is still unknown. In this study, specimens were prepared through the replacement of cement with 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, and 5 wt.% TiO2 nanoparticles and cured under temperatures of 0°C, 5°C, 10°C, and 20°C for specific ages. Physical and mechanical properties of the specimens were evaluated through the setting time test, compressive strength test, flexural strength test, hydration degree test, mercury intrusion porosimetry (MIP), X-ray diffraction (XRD) analysis, thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM) in order to examine the performance of cementitious materials with and without TiO2 nanoparticles at various curing temperatures. It was found that low temperature delayed the process of cement hydration while TiO2 nanoparticles had a positive effect on accelerating the cement hydration and reducing the setting time in terms of the results of the setting time test, hydration degree test, and strength test, and the specimen with the addition of 2 wt.% TiO2 nanoparticles showed the superior performance. Refined pore structure in the MIP tests, more mass loss of CH in TGA, intense peak appearance associated with the hydration products in XRD analysis, and denser microstructure in SEM demonstrated that the specimen with 2 wt.% TiO2 nanoparticles exhibited preferable physical and mechanical properties compared with that without TiO2 nanoparticles under various curing temperatures.

Mechanical properties and freeze-thaw resistances of bronze-concrete composites

2021 ◽  
Vol 12 (2) ◽  
pp. 39
Author(s):  
Tuba Bahtli ◽  
Nesibe Sevde Ozbay
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Test Methods ◽  
Pulse Velocity ◽  
Plastic Energy ◽  
Freeze Thaw ◽  
Schmidt Rebound Hammer

Studies in the literature show that the physical and mechanical properties of concrete could be improved by the incorporation of different kinds of industrial waste, including waste tire rubber and tire steel. Recycling of waste is important for economic gain and to curb environmental problems. In this study, finely ground CuAl10Ni bronze is used to improve the physical and mechanical properties, and freeze-thaw resistances of C30 concrete. The density, cold crushing strength, 3-point bending strength, elastic modulus, toughness, and freeze-thaw resistances of concrete are determined. In addition, the Schmidt Rebound Hammer (SRH) and the ultrasonic pulse velocity (UPV) tests, which are non-destructive test methods, are applied. SEM/EDX analyses are also carried out. It is noted that a more compacted structure of concrete is achieved with the addition of bronze sawdust. Then higher density and strength values are obtained for concretes that are produced by bronze addition. In addition, concretes including bronze sawdust generally show higher toughness due to high plastic energy capacities than pure concrete.

scholarly journals Antibacterial Effect and Physical-Mechanical Properties of Temporary Restorative Material Containing Antibacterial Agents

2015 ◽  
Vol 2015 ◽  
pp. 1-5
Author(s):  
Amanda Mahammad Mushashe ◽  
Carla Castiglia Gonzaga ◽  
Paulo Henrique Tomazinho ◽  
Leonardo Fernandes da Cunha ◽  
Denise Piotto Leonardi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compression Strength ◽  
Water Sorption ◽  
Antibacterial Agents ◽  
Antibacterial Effect ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
Diffusion Method ◽  
Restorative Material ◽  
Significant Difference

Introduction. For the maintenance of the aseptic chain created during the treatment the coronal sealing becomes paramount. Aim. Evaluating the antibacterial effect and the physical-mechanical properties of a temporary restorative material containing different antibacterial agents. Material and Methods. Two antibacterial agents (triclosan and chloramine T) were manually added to a temporary restorative material used as base (Coltosol). The antibacterial action of the material was analyzed using the agar diffusion method, in pure cultures of Escherichia coli (ATCC BAA-2336) and Staphylococcus aureus (ATCC 11632) and mixed culture of saliva collection. The microleakage rate was analyzed using bovine teeth, previously restored with the materials, and submitted to thermocycling, in a solution of 0.5% methylene blue, for a period of 24 hours. The physical and mechanical properties of the materials analyzed were setting time, water sorption, solubility, and compression strength. Results. No marginal leakage was observed for all groups. There was no statistical significant difference in antimicrobial activity, setting time, water sorption, solubility, and compression strength among the materials. Conclusion. The addition of antibacterial agents on a temporary restorative material did not optimize the antibacterial ability of the material and also did not change its physical-mechanical properties.

EXPERIMENTAL RESULTS ON THE SHEAR BEHAVIOUR OF STEEL FIBRE SELF-COMPACTING CONCRETE (SFSCC) BEAMS

2016 ◽  
Vol 78 (11) ◽  
Author(s):  
Juli Asni Lamide ◽  
Roslli Noor Mohamed ◽  
Ahmad Baharuddin Abd Rahman
Keyword(s):  
Mechanical Properties ◽  
Steel Fibre ◽  
Mechanical Performance ◽  
Load Capacity ◽  
Shear Behaviour ◽  
Self Compacting Concrete ◽  
Steel Fibres ◽  
Concrete Mixtures ◽  
Shear Performance ◽  
Better Than

This paper presents an experimental test program that was carried out to investigate the shear performance of steel fibre self-compacting concrete (SFSCC) beams. In this paper, the mechanical performance of results from all mixtures used to cast normal concrete (NC), self-compacting concrete (SCC) and steel fibre self-compacting concrete (SFSCC) were also investigated. In total, 27 cubes, 9 cylinders, 9 prisms and 9 beams were prepared for the assessment of mechanical properties of three different mixtures. Four beams (125 mm x 250 mm x 2200 mm) were tested and cast using three different concrete mixtures, having two different spacing of stirrups as a result of 50% reduction of the stirrups amount. Three beams with different mixtures having similar stirrups spacing 125mm while the fourth beam with SFSCC mixes having 250mm stirrups spacing. The results show that the mechanical properties were positively affected with steel fibres inclusion. The addition of steel fibres showed an increment up to 40% in the shear load capacity for B-SFSCC125 compared to B-NC125 and B-SCC125.  In addition, the crack pattern of B-SFSCC was found better than B-NC and B-SCC.   

scholarly journals Effect of fly ash on physical and mechanical properties of mortar

2019 ◽  
Vol 17 (6) ◽  
pp. 35
Author(s):  
Vu-An Tran
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Water Absorption ◽  
Thermal Power ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
Flow Density ◽  
Control Specimen

This research investigates the physical and mechanical properties of mortar incorporating fly ash (FA), which is by-product of Duyen Hai thermal power plant. Six mixtures of mortar are produced with FA at level of 0%, 10%, 20%, 30%, 40%, and 50% (by volume) as cement replacement and at water-to-binder (W/B) of 0.5. The flow, density, compressive strength, flexural strength, and water absorption tests are made under relevant standard in this study. The results have shown that the higher FA content increases the flow of mortar but significantly decreases the density of mixtures. The water absorption and setting time increases as the samples incorporating FA. Compressive strength of specimen with 10% FA is approximately equal to control specimen at the 91-day age. The flexural strength of specimen ranges from 7.97 MPa to 8.94 MPa at the 91-day age with the best result for samples containing 10% and 20% FA.

scholarly journals Physical and Mechanical Properties of Self-Compacting Concrete (SCC) with Pineapple Leaf Fibre and Polypropylene

2021 ◽  
Vol 1783 (1) ◽  
pp. 012077
Author(s):  
Hanoora Sarah Anindita Hendrian ◽  
Saloma ◽  
Hanafiah ◽  
Maulid M. Iqbal ◽  
Ika Juliantina
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Self Compacting Concrete
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