scholarly journals Impact Response of Preplaced Aggregate Fibrous Concrete Hammerhead Pier Beam Designed with Topology Optimization

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 147
Author(s):  
Meivazhisalai Parasuraman Salaimanimagudam ◽  
Gunasekaran Murali ◽  
C. M. Vivek Vardhan ◽  
Mugahed Amran ◽  
Nikolai Vatin ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Impact Strength ◽  
Initial Crack ◽  
Impact Response ◽  
Index Number ◽  
Tension Zone ◽  
Full Cross Section ◽  
Secondary Cracks ◽  
Fibrous Concrete ◽  
The Impact

This research aimed to study the impact response of topology optimized hammerhead pier beam (HPB) based on the density approach. The HPB is prepared with the concept of preplaced aggregate fibrous concrete (PAFC) comprising two primary approaches; first, the coarse aggregate and fiber are prepacked into the designed formwork. Second, the gaps between the aggregate and fiber are filled with cement grout. In this work, an attempt has been made to study an impact response of HPB made with PAFC. Five HPBs were prepared and strengthened with steel fibers with two different schemes, Firstly, the HPB was reinforced with a full cross-section at 2 and 4% of steel fiber, while another set of beams were only reinforced in the tension zone with the same amount of fibers. The study parameters included compressive strength, impact strength, impact ductility index, number of main and secondary cracks, and failure pattern. It was observed that the PAFC had an increase in compressive strength up to 56.9%, compared with nonfibred concrete. A fully fibered concrete beam with 4% fiber addition was the best at taking impact, and the initial crack and failures were observed at 2725.1 J and 3009.8 J, respectively, compared with non-fibered and tension zone fibered concrete beams. Compressive local damage and transverse flexural cracks were observed, which had caused initial cracks and final failure. The HPB with a full reinforced scheme at 4% dosage exhibited higher impact strength than the normal concrete and beam reinforced only in the tension zone.

scholarly journals Comparison of Dental Stone Models and Their 3D Printed Acrylic Replicas for the Accuracy and Mechanical Properties

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4066
Author(s):  
Marta Czajkowska ◽  
Ewa Walejewska ◽  
Łukasz Zadrożny ◽  
Monika Wieczorek ◽  
Wojciech Święszkowski ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Impact Strength ◽  
Physical Properties ◽  
Diagnostic Tool ◽  
Medical Records ◽  
Diagnostic Value ◽  
Dental Models ◽  
3D Printed ◽  
The Impact

This study was conducted to test possibilities of application of 3D printed dental models (DMs) in terms of their accuracy and physical properties. In this work, stone models of mandibles were cast from alginate impressions of 10 patients and scanned in order to obtain 3D printed acrylic replicas. The diagnostic value was tested as matching of model scans on three levels: peak of cusps, occlusal surface, and all teeth surfaces. The mechanical properties of acrylic and stone samples, specifically the impact strength, shore D hardness, and flexural and compressive strength were investigated according to ISO standards. The matching of models’ surfaces was the highest on the level of peaks of cusps (average lack of deviations, 0.21 mm) and the lowest on the level of all teeth surfaces (average lack of deviations, 0.64 mm). Acrylic samples subjected to mechanical testing, as expected, showed higher mechanical properties as compared to the specimens made of dental stone. In the present study we demonstrated that 3D printed acrylic models could be ideal representatives in the case of use as a diagnostic tool and as a part of medical records. The acrylic samples exhibited not only higher mechanical properties, but also showed better accuracy comparing to dental stone.

scholarly journals Increasing the Performance of a Fiber-Reinforced Concrete for Protective Facilities

Fibers ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 64
Author(s):  
Roman Fediuk ◽  
Mugahed Amran ◽  
Sergey Klyuev ◽  
Aleksandr Klyuev
Keyword(s):  
Reinforced Concrete ◽  
Impact Strength ◽  
Impact Energy ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Secondary Cracks ◽  
Wide Range ◽  
Long Time ◽  
The Impact ◽  
Hardening Coefficient

The use of fiber in cement materials is a promising and effective replacement for bar reinforcement. A wide range of fiber-reinforced concretes based on composite binders with increased impact strength characteristics have been developed. The synthesized composites included the composite binder made of Portland cement, silica, and carbonate additives. Basalt and steel were used as fibers. The nature of the influence of the composition and manufacturing technology of cement composites on the dynamic hardening coefficient has been established, while the growth of these indicators is achieved by creating a denser interfacial transition zone between the cement paste, aggregate, and fiber as a result of improving the homogeneity of the concrete mixture and controlling the consistency. Workability indicators (slump flow up to 730 mm; spreading time up to a diameter of 50 cm is up to 3 s) allow them to be classified as self-compacting concrete mixtures. An increase in the values of the impact strength coefficient by a factor of 5.5, the dynamic hardening coefficient by almost 70% as a result of interfacial interaction between fibers and binder matrix in the concrete composite, as well as absorption of impact energy by fiber, was revealed. The formula describing the effect of the loading rate on the coefficient of dynamic hardening of fiber-reinforced concrete has been refined. The fracture processes of the obtained materials have been established: after the initiation of primary cracks, the structure of the composite absorbs impact energy for a long time, while in the inelastic range (the onset of cracking and peak loads), a large number of secondary cracks appear.

Study of mechanical properties of pultruded jute-glass reinforced unsaturated polyester bio-composites with hybrid filler loading

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Navin Kumar ◽  
Ravinderjit Singh Walia ◽  
Surjit Angra
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Impact Strength ◽  
Filler Loading ◽  
Hybrid Filler ◽  
Content Type ◽  
Hybrid Fibre ◽  
Hybrid Fillers ◽  
Set Up ◽  
The Impact

Purpose The purpose of this study is to develop jute-glass hybrid fibre reinforced polyester-based bio-composites using an indigenously developed pultrusion set-up and to present a detailed discussion on their mechanical characterization. Design/methodology/approach The work was carried out to observe the hybridization effect of natural and synthetic fibres in combination with hybrid fillers loading mainly on strength and other properties. The used hybrid fillers were a combination of 9 Wt.% of carbon black%, 6 Wt.% of eggshell ash powder and 6 Wt.% of coconut coir ash powder. A lab-based developed pultrusion set-up was used to develop these hybrid GJFRP composites of 1,500 mm length. The developed composites were tested for tensile strength, compressive strength and impact strength. Findings The maximum tensile, compressive and impact strength obtained are 88.37 MPa, 56.13 MPa and 731.91 J/m from 9 Wt.%, 9 Wt.% and 0 Wt.% of hybrid fillers loading, respectively. Breaking energy was found maximum as 7.31 J in hybrid glass-jute hybrid fibre reinforced plastic composites with no filler loading and it was observed that filler loading was decreasing the impact strength of developed hybrid composites. Shrinkage and its variations in the diameter of the finally developed cylindrical shape composites were observed after cooling and solidification. Scanning electron microscopy was used to observe the internal cracks, bonding of fibres and resin, voids, etc. Originality/value Development of hybrid filler based novel eco-friendly bio-composites and its experimental investigation on the impact strength, tensile strength and compressive strength has not been attempted yet.

scholarly journals Properties of Pavement Quality Concrete Prepared with Recycled Coarse Aggregate

2020 ◽  
Vol 8 (5) ◽  
pp. 3186-3192 ◽  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Impact Strength ◽  
Flexural Strength ◽  
Coarse Aggregate ◽  
Strength Characteristics ◽  
Laboratory Environment ◽  
Recycled Coarse Aggregate ◽  
The Impact ◽  
Remarkable Reduction

The investigation is intended to evaluate the impact of substitution of demolished concrete debris as coarse aggregate (CA) in pavement quality concrete (PQC). The strength characteristics of PQC such as compressive strength, tensile strength, flexural strength and impact strength after adding recycled coarse aggregate (RCA) are experimentally determined in laboratory environment. Specimens of M30 grade concrete were prepared and tested. The RCA was substituted up to 50% by replacing CA content. Based on the investigation results, it was found that reduction of slump value due to the substitution of RCA in concrete. There is no remarkable reduction of compressive strength and flexural strength up to 30% and 40 % replacement of CA respectively in all the curing periods. The impact strength was reduced due to addition of RCA and observed 8% reduction after adding 20% RCA. It is suggested that RCA may be used up to 20% as CA in PQC.

Mechanical properties of cured epoxy resin

2021 ◽  
Author(s):  
Sergey Savotchenko ◽  
Ekaterina Kovaleva
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Impact Strength ◽  
Epoxy Resin ◽  
Mass Fraction ◽  
Mechanical Characteristics ◽  
Bending Strength ◽  
The Impact ◽  
Impact Viscosity

We study experimentally the influence of mass fraction of L-20 hardener cold cure on mechanical properties of epoxy diane resin ED-20. We measure the hardness, tensile strength, bending strength and impact strength of resin at different values of the hardener mass fraction. It is found that the ratio hardener mass fraction of 1:0.9 leads to the highest values of the hardness, tensile strength, compressive strength and bending strength. The impact viscosity is maximum at the ratio hardener mass fraction of 1:0.8. The optimal ratio of a non-toxic safe hardener to the resin is derived based on obtained mechanical characteristics.

scholarly journals Polyurethane Hybrid Composites Reinforced with Lavender Residue Functionalized with Kaolinite and Hydroxyapatite

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 415
Author(s):  
Sylwia Członka ◽  
Agnė Kairytė ◽  
Karolina Miedzińska ◽  
Anna Strąkowska
Keyword(s):  
Thermal Decomposition ◽  
Compressive Strength ◽  
Impact Strength ◽  
Flexural Strength ◽  
Flame Retardant ◽  
Hybrid Composites ◽  
Thermal Characteristic ◽  
Flame Resistance ◽  
Limiting Oxygen Index ◽  
The Impact

Polyurethane (PUR) composites were modified with 2 wt.% of lavender fillers functionalized with kaolinite (K) and hydroxyapatite (HA). The impact of lavender fillers on selected properties of PUR composites, such as rheological properties (dynamic viscosity, foaming behavior), mechanical properties (compressive strength, flexural strength, impact strength), insulation properties (thermal conductivity), thermal characteristic (temperature of thermal decomposition stages), flame retardancy (e.g., ignition time, limiting oxygen index, heat peak release) and performance properties (water uptake, contact angle) was investigated. Among all modified types of PUR composites, the greatest improvement was observed for PUR composites filled with lavender fillers functionalized with kaolinite and hydroxyapatite. For example, on the addition of functionalized lavender fillers, the compressive strength was enhanced by ~16–18%, flexural strength by ~9–12%, and impact strength by ~7%. Due to the functionalization of lavender filler with thermally stable flame retardant compounds, such modified PUR composites were characterized by higher temperatures of thermal decomposition. Most importantly, PUR composites filled with flame retardant compounds exhibited improved flame resistance characteristics—in both cases, the value of peak heat release was reduced by ~50%, while the value of total smoke release was reduced by ~30%.

scholarly journals Effect of High Temperatures on the Impact Strength of Concrete Based on Recycled Aggregate Made of Heat-Resistant Cullet

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 465 ◽  
Author(s):  
Aleksandra Powęzka ◽  
Jacek Szulej ◽  
Paweł Ogrodnik
Keyword(s):  
Compressive Strength ◽  
Impact Strength ◽  
Testing Procedure ◽  
Recycled Aggregate ◽  
Test Results ◽  
Heat Resistant ◽  
Temperature Impact ◽  
The Impact ◽  
Average Compressive Strength ◽  
By Products

The article presents results obtained during testing of concrete based on CEM I 42.5R Portland cement, fine and coarse aggregate, glass, volatile ash, and superplastifier. The concrete mixture was modified using filler consisting of bromosilicate heat resistant cullet. Recycled aggregate was added to the batch. Samples for the need of testing were produced as (100 × 100 × 100) mm cubes. Before commencing proper tests, samples have been heated within the temperature range of 20–800 °C. Tests carried out during the proper testing procedure included tests of compressive strength, elevated temperature, impact strength, as well as macroscopic tests of the contact area. The obtained test results have provided proof of there being a possibility of producing special concrete, modified by products obtained from heat resistant cullet. This type of is generally characterized by satisfactory performance parameters. The average compressive strength for concrete modified by a 10% of heat resistant cullet was determined as 43.6 MPa and 48.3 MPa respectively after 28 and 180 days of curing.

scholarly journals Polyurethane Composites Reinforced with Walnut Shell Filler Treated with Perlite, Montmorillonite and Halloysite

2021 ◽  
Vol 22 (14) ◽  
pp. 7304
Author(s):  
Sylwia Członka ◽  
Agnė Kairytė ◽  
Karolina Miedzińska ◽  
Anna Strąkowska
Keyword(s):  
Thermal Decomposition ◽  
Compressive Strength ◽  
Impact Strength ◽  
Flexural Strength ◽  
Flame Retardant ◽  
Thermal Characteristic ◽  
Walnut Shell ◽  
Flame Resistance ◽  
Limiting Oxygen Index ◽  
The Impact

In the following study, polyurethane (PUR) composites were modified with 2 wt.% of walnut shell filler modified with selected mineral compounds–perlite, montmorillonite, and halloysite. The impact of modified walnut shell fillers on selected properties of PUR composites, such as rheological properties (dynamic viscosity, foaming behavior), mechanical properties (compressive strength, flexural strength, impact strength), dynamic-mechanical behavior (glass transition temperature, storage modulus), insulation properties (thermal conductivity), thermal characteristic (temperature of thermal decomposition stages), and flame retardant properties (e.g., ignition time, limiting oxygen index, heat peak release) was investigated. Among all modified types of PUR composites, the greatest improvement was observed for PUR composites filled with walnut shell filler functionalized with halloysite. For example, on the addition of such modified walnut shell filler, the compressive strength was enhanced by ~13%, flexural strength by ~12%, and impact strength by ~14%. Due to the functionalization of walnut shell filler with thermally stable flame retardant compounds, such modified PUR composites were characterized by higher temperatures of thermal decomposition. Most importantly, PUR composites filled with flame retardant compounds exhibited improved flame resistance characteristics-in all cases, the value of peak heat release was reduced by ~12%, while the value of total smoke release was reduced by ~23%.

Fly ash-based green composite as pipe, gear and blade

2018 ◽  
Vol 15 (1) ◽  
pp. 40-47
Author(s):  
Jenarthanan MP ◽  
Ramesh Kumar S. ◽  
Akhilendra Kumar Singh
Keyword(s):  
Experimental Investigation ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Impact Strength ◽  
Flexural Strength ◽  
Axial Flow ◽  
Green Composites ◽  
Content Type ◽  
The Impact

Purpose This paper aims to perform an experimental investigation on the impact strength, compressive strength, tensile strength and flexural strength of fly ash-based green composites and to compare with these polyvinyl chloride (PVC), high density polyethylene (HDPE) and low density polyethylene (LDPE). Design/methodology/approach Fly ash-based polymer matrix composites (FA-PMCs) were fabricated using hand layup method. Composites containing 100 g by weight fly ash particles, 100 g by weight brick dust particles and 50 g by weight chopped glass fiber particles were processed. Impact strength, compressive strength, tensile strength and flexural strength of composites have been measured and compared with PVC, HDPE and LDPE. Impact strength of the FA-PMC is higher than that of PVC, HDPE and LDPE. Structural analysis of pipes, gears and axial flow blade was verified using ANSYS. Barlou’s condition for pipes, Lewis–Buckingham approach for gears and case-based analysis for axial flow blades were carried out and verified. Findings Pipes, gears and axial flow blades made form fly ash-based composites were found to exhibit improved thermal resistance (i.e. better temperature independence for mechanical operations), higher impact strength and longer life compared to those made from PVC, HDPE and LDPE. Moreover, the eco-friendly nature of the raw materials used for fabricating the composite brings into its quiver a new dimension of appeal. Originality/value Experimental investigation on the impact strength, compressive strength, tensile strength and flexural strength of fly ash-based green composites has not been attempted yet.

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