scholarly journals THE INFLUENCE OF GRANITE SIFTINGS ON THE PROPERTIES OF CLEAVED SURFACE EXTERIOR CONCRETE BRICKS

2010 ◽  
Vol 2 (6) ◽  
pp. 43-49 ◽  
Author(s):  
Mindaugas Tumosa ◽  
Mindaugas Daukšys ◽  
Ernestas Ivanauskas
Keyword(s):  
Mechanical Properties ◽  
Concrete Mixture ◽  
Fine Aggregate ◽  
Technological Properties ◽  
Product Durability

Research deals with granite siftings as fine aggregate possibilities to be used for manufacturing cleaved surface exterior concrete bricks. The article describes the influence of granite siftings on the technological properties of concrete mixture and on the physical mechanical properties of cleaved surface exterior concrete bricks formed using these mixtures and forecasts product durability. The following several compositions of concrete mixture for producing exterior concrete bricks are composed: using only 0/4 fraction sand (B1) as a fine aggregate, using only 0/2 fraction granite siftings (B2), and 50% of 0/4 fraction sand replacing with 0/2 fraction granite siftings (B3) depending on the volume. The products were formed in metal moulds; at a later stage, they were cleaved in half. The technological properties of concrete mixture and the physical mechanical properties of cleaved surface exterior concrete bricks formed using the above introduced mixtures were tested forecasting product durability. The results of the conducted research reveal that due to the properly selected ratio between sand and granite siftings in the fine aggregate, granite siftings may be used for manufacturing cleaved surface exterior concrete bricks.

scholarly journals INFLUENCE OF THE GRANITE SCREENINGS TO THE PROPERTIES OF THE CONCRETE PAVING BLOCKS

2012 ◽  
Vol 4 (3) ◽  
pp. 89-95
Author(s):  
Mindaugas Laurinavičius ◽  
Mindaugas Daukšys ◽  
Albertas Klovas
Keyword(s):  
Mechanical Properties ◽  
Frost Resistance ◽  
Physical And Mechanical Properties ◽  
Concrete Mixture ◽  
Fine Aggregate ◽  
Technological Properties ◽  
Research Results ◽  
Concrete Mixtures ◽  
Better Than ◽  
Durability Of Concrete

The research deals with the granite screenings as fine aggregate influence on the technological properties of concrete mixtures and on the physical and mechanical properties and durability of concrete paving. The following several compositions of concrete mixture for the production of environment arrangements are researched: fine aggregate using only 0/2 fraction sand (B1), 10% of 0/2 fraction sand replacing with 0/2 fraction granite screenings (B2) and using only granite screenings (B3). Concrete mixtures were prepared in the laboratory, and concrete paving blocks – in the factory. The technological properties of concrete mixtures and physical and mechanical properties of concrete paving blocks (made from the mentioned concrete mixtures) were determined; the durability of the products in the cycles of frost resistance was forecasted. The research results reveal that due to the properly selected ratio between sand and granite screenings in the fine aggregate, the characteristics of concrete paving blocks are better than using only sand as fine aggregate.

scholarly journals INFLUENCE OF MINERAL AGGREGATE CONCENTRATION ON THE TECHNOLOGICAL PROPERTIES OF FRESH CONCRETE MIXTURE / MINERALINIŲ UŽPILDŲ KONCENTRACIJOS ĮTAKA ŠVIEŽIO BETONO MIŠINIO TECHNOLOGINĖMS SAVYBĖMS

2013 ◽  
Vol 5 (2) ◽  
pp. 54-60 ◽  
Author(s):  
Albertas Klovas ◽  
Mindaugas Daukšys ◽  
Gintas Brazas
Keyword(s):  
Fine Particles ◽  
Fresh Concrete ◽  
Flow Characteristics ◽  
Concrete Mixture ◽  
Fine Aggregate ◽  
Technological Properties ◽  
Sand Fraction ◽  
Mineral Aggregate ◽  
Air Content ◽  
Slump Flow

The main aim of this research was to investigate how the concentration of mineral aggregate influences the technological properties of concrete mixture such as: slump, flow characteristics and air content, as well as the density of concrete mixture. To sum up, 18 concrete mixture compositions were casted. First six compositions were casted in order to establish the dependence between the ratio of fine aggregate (sand fraction: 0/1 and 0/4) and the technological properties of fresh concrete mixture. Another six compositions were casted in order to investigate the link between course aggregate (gravel, fraction 4/16) concentration and the concrete mixture's technological properties. The last six mixtures were casted in order to test how the amount of fine particles (not exceeding 0.25 mm in diameter) influences the concrete mixture's technological properties. Santrauka Pagrindinis šio tyrimo tikslas – nustatyti, kaip mineralinių užpildų koncentracija veikia technologines betono mišinio savybes: slankumą, sklidumą, oro kiekį ir mišinio tankį. Iš viso buvo tirta 18 skirtingų betono mišinio sud≑čių. Pirmosios šešios sudėtys buvo analizuojamos siekiant nustatyti priklausomybę tarp smulkaus užpildo koncentracijos (smėlio frakcijos: 0/1 bei 0/4) ir technologinių betono mišinio savybių. Kitos šešios sudėtys buvo analizuojamos siekiant rasti priklausomybę tarp stambaus užpildo koncentracijos (žvirgždo frakcija 4/16) ir technologinių betono mišinio savybių. Paskutinės šešios betono mišinio sudėtys buvo analizuojamos siekiant nustatyti smulkiųjų dalelių, kurių skersmuo neviršija 0,25 mm, kiekio įtaką technologinėms betono mišinio savybėms.

Mechanical Properties of Concrete Incorporating Pre-Treated Wastes Sawdust

2021 ◽  
Vol 895 ◽  
pp. 147-156
Author(s):  
Esam Hewayde ◽  
Ziyad Kubba
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Calcium Hydroxide ◽  
The Other ◽  
Concrete Mixture ◽  
Fine Aggregate ◽  
Distilled Water ◽  
Concrete Mixtures ◽  
Slaked Lime ◽  
Pre Treatment

This paper investigates the effect of using wastes sawdust as a replacement of fine aggregate (sand) on mechanical properties naming compressive, tensile and flexural strengths of ordinary Portland concrete. The wastes sawdust was treated before incorporating it in concrete mixtures. Three different methods were used to pre-treat the sawdust including a) soaking the sawdust in distilled water at 50 oC, b) soaking the sawdust in Ca (OH)2 solution, and c) soaking the sawdust in Ca (OH)2 solution and using a set accelerator in the concrete mixture. In addition to the control mixture (having no sawdust), three more concrete mixtures were prepared to explore the effect of the three different methods of pre-treatment on the mechanical properties of concrete. Results showed that the compressive strength of the concrete incorporating wastes sawdust pre-treated with the calcium hydroxide solution (slaked lime) and having the accelerator was higher than that of the control mixture. The tensile and flexural strengths of the concrete mixture having waste sawdust pre-treated by Ca (OH)2 solution and having the accelerator were found to be very comparable to those of the control mixture. On the other hand, the compressive, tensile, and flexural strengths of the concrete mixture with sawdust pre-treated by Ca (OH)2 solution only were somehow comparable to those of concrete mixture having sawdust pre-treated by distilled water. While the compressive strength of the concrete mixtures incorporating sawdust pre-treated with either Ca (OH)2 solution or distilled water was less than that of the control mixture, both tensile and flexural strengths of the two treated concrete mixtures were approximately comparable to those of the control mixture.

Study of Rheological Properties of Modified Concrete Mixtures at Vibration

2019 ◽  
Vol 968 ◽  
pp. 96-106
Author(s):  
Oleksandr Pshinko ◽  
Olena Hromova ◽  
Dmytro Rudenko
Keyword(s):  
Mechanical Properties ◽  
Rheological Properties ◽  
Physical Nature ◽  
Concrete Mixture ◽  
Practical Significance ◽  
Vibration Displacement ◽  
Concrete Mixtures ◽  
Variable Quantity ◽  
Vibration Compaction ◽  
Mechanism Of Interaction

Study of rheological properties of concrete mixtures based on modified cement systems in order to determine process parameters. Methodology. To study structural-mechanical properties of modified concrete mixtures of different consistency at their horizontal vibrating displacement an oscillatory viscometer was designed. Results. The optimization of the process of vibration displacement of concrete mixtures with the specification of parameters of vibration impacts taking into account structural-mechanical properties of the mixture is performed. It has been established that the viscosity of the modified cement system of the concrete mixture is a variable quantity, which depends on the parameters of the vibration impacts. Scientific novelty. The mechanism of interaction of the modified concrete mixture with the form and the table vibrator during its vibration compaction is determined. On the basis of this, a model of concrete laying process control is proposed, that allows to predict the ability to form a dense concrete structure. Practical significance. Disclosed physical nature of the process of vibrating displacement of modified concrete mixtures using the principles of physical-chemical mechanics of concrete allows reasonably choose the best options for vibration impacts.

scholarly journals Engineering and Manufacturing Technology of Green Epoxy Resin Coatings Modified with Recycled Fine Aggregates

2021 ◽  
Author(s):  
Kamil Krzywiński ◽  
Łukasz Sadowski ◽  
Damian Stefaniuk ◽  
Aleksei Obrosov ◽  
Sabine Weiß
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Construction And Demolition Waste ◽  
Fine Aggregate ◽  
Micro Computed Tomography ◽  
Demolition Waste ◽  
Replacement Ratio ◽  
Recycled Fine Aggregate ◽  
Fine Aggregates ◽  
Computed Tomography Scanning

AbstractNowadays, the recycled fine aggregate sourced from construction and demolition waste is not frequently used in manufacturing of epoxy resin coatings. Therefore, the main novelty of the article is to prepare green epoxy resin coatings modified with recycled fine aggregate in a replacement ratio of natural fine aggregate ranged from 20 to 100%. The microstructural properties of the aggregates and epoxy resin were analyzed using micro-computed tomography, scanning electron microscopy and nanoindentation. The macroscopic mechanical properties were examined using pull-off strength tests. The highest improvement of the mechanical properties was observed for epoxy resin coatings modified with 20% of natural fine aggregate and 80% of recycled fine aggregate. It has been found that even 100% of natural fine aggregate can be successfully replaced using the recycled fine aggregate with consequent improvement of the pull-off strength of analyzed epoxy resin coatings. In order to confirm the assumptions resulting from the conducted research, an original analytical and numerical failure model proved the superior behavior of modified coating was developed.

Influence of High-Calcium Ash Composition on the Composite Binders’ Properties

2021 ◽  
Vol 316 ◽  
pp. 1019-1024
Author(s):  
O. A. Ignatova ◽  
A. A. Dyatchina
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Cement Stone ◽  
Normal Density ◽  
Fine Aggregate ◽  
Equivalent Amount ◽  
High Calcium ◽  
Composition Structure ◽  
Kinetics Of ◽  
Positive Effect

The paper presents the studies’ results of chemical composition, structure, and physico-mechanical properties of high-calcium ashes from the Kansk-Achinsk coals (2017-2019 selection). It was found that ash has a complex poly-mineral composition and contains hydraulically active minerals and oxides of СаОfr, β-C2S, CA, C3A, C4AF, C2F, CaSO4. According to the content of CaOfr, MgO does not meet standards’ requirements. The uniformity of the volume change is maintained by the composition with 50% of cement. The structure and hardening kinetics of ash and ash-cement stone compositions, obtained from the test of normal density, were analyzed. It was established that the hardening of compositions with ash from the Kansk-Achinsk coals was largely influenced by ash minerals. An equivalent amount of cement in composite binders cannot be replaced. In order to obtain a positive effect, compositions with ash instead cement of no more than 30% and a part of fine aggregate, without exceeding the ratio of ash: cement = 1: 1, should be used.

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