scholarly journals Flexural Behaviour of Cementitious Mortars with the Addition of Basalt Fibres

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1334
Author(s):  
Małgorzata Wydra ◽  
Piotr Dolny ◽  
Grzegorz Sadowski ◽  
Jadwiga Fangrat

The results of flexural tests of basalt fibre-reinforced cementitious mortars in terms of flexural strength and the occurrence of the bridging effect are summarised. Mixture proportions and curing conditions were altered for various series. The main parameters concerning mixture proportions were water to cement ratio (w/c), micro-silica and plasticiser addition and fibre dosage (1%, 3% and 6.2% by binder’s mass). Various curing conditions were defined by different temperatures, humidity and time. The influence of the amount of water inside the pores of the hardened cementitious matrix on the flexural strength values, as far as the impact of the alkaline environment on basalt fibres’ performance is concerned, was underlined. The designation of flexural strength and the analysis of post-critical deformations were also performed on the reference series without fibres and with the addition of more common polypropylene fibres. The bridging effect was observed only for the basalt fibre-reinforced mortar specimens with a relatively low amount of cement and high w/c ratio, especially after a short time of hardening. For the lowest value of w/c ratio (equalling 0.5), the bridging effect did not occur, but flexural strength was higher than in the case of non-reinforced specimens. Comparing mortars with the addition of basalt and polypropylene fibres, the former demonstrated higher values of flexural strength (assuming the same percentage dosage by the mass of the binder). Nevertheless, the bridging effect in that case was obtained only for polypropylene fibres.

2014 ◽  
Vol 879 ◽  
pp. 90-95 ◽  
Author(s):  
Abdul Rahman Noor Leha ◽  
Nor Amalina Nordin

Biocomposite from bamboo powder was fabricated by compression molding technique. The objective of this study was to investigate the mechanical properties of bamboo compounded with epoxy with different ratio. Tensile and flexural tests were done to characterize its mechanical properties. It was observed that the strength of bamboo-polyester was increased with increasing amount of bamboo powder. The tensile and flexural strength shows the highest value at 25 wt.% bamboo. However, the impact test shows the maximum value at 20 wt.% bamboo powder. These results exhibit the bamboo-polyester can be a good candidate to be used in many engineering applications


2020 ◽  
Vol 55 (1) ◽  
pp. 95-107
Author(s):  
Alireza Mansoori ◽  
Mohammad Mohtasham Moein ◽  
Ehsan Mohseni

This paper aims to evaluate the impact of ceramic waste powder (CWP), micro silica (MS) and steel fiber (SF) on self-compacting mortar. CWP at ratios of 10 and 20%, and MS at 1 and 5% by weight of cement were replaced the cement. Beside, SF was added at ratios of 0.5 and 1% of cement. Mini slump flow diameter and mini V-funnel flow time tests were carried out to determine the workability of fresh composites. Compressive strength, flexural strength, water absorption, electrical resistivity and drying shrinkage tests were performed on hardened mortars. Scanning electron microscope (SEM) technique was employed to assess the microstructure. The results indicated that CWP reduced the mechanical properties by about 20% and increased permeability by about 14%. However, inclusion of micro silica particles improved the properties outstandingly. Compressive strength increased about 30% by inclusion of MS. It was also observed that the addition of fibers from 0.5% to 1% increased the flexural strength. This improvement was more obvious in samples with higher contents of micro silica. It can be reported that by including the both micro silica and steel fibers, the bonding between the cement paste and fibers was developed. Replacement of micro silica led to increase of electrical resistivity by about 99% in samples containing 20% ceramic waste powder. The microstructure studies confirmed the significant increase of density and uniformity of the hydration products in the presence of micro silica particles.


Concrete as a building material, used most extensively has revolutionized the construction industry by its properties like high strength and workability. However, the engineering structures are surrounded by the combustible materials, making them prone to the blast impact loading as well as fire. Concrete structures which are subjected to the conditions of high temperature, are susceptible to physical and chemical changes leading to their degradation. The fire can cause the damage to the structure as well as human lives. The need of the hour is to study the impact of fire on the concrete structures as it is mostly used as the construction entity in buildings and other structures. In our research paper, the use of Polypropylene fibers (PPFs) in concrete and their impact on various attributes of concrete like Compression stréngth, split tensile and flexurál strength has been studied. The impact of PPFs on concrete at different temperatures has also been analyzed. The results have shown that the compression strength got raised due to the inclusion of PPFs in the concrete by 9.08%, splitting tensile by 59.25% and flexural strength by 27.36% after 4 weeks of curing. The addition of PPFs to the concrete has also resulted in an increase in strength then the conventional concrete at temperatures of 400oC and 800oC.


2019 ◽  
Vol 31 (2) ◽  
Author(s):  
Samson Olalekan Odeyemi ◽  
Rasheed Abdulwahab ◽  
Adebayo Akeem Abdulsalam ◽  
Mukaila Abiola Anifowose

Self-compacting concrete (SCC) is an innovative concrete that has helped in overcoming challenges associated with vibrated concrete such as congested reinforcements, noise from vibrators, and cost of hiring vibrators. This research examined the bond strength between partially replaced Self Compacting Palm Kernel Shell (SCPKS) concrete and high yield reinforcing bars wherein the granite content of the concrete was replaced by 50% of palm kernel shell (total replacement disintegrated on removal of mould). SCPKS concrete specimens of mix ratios 1:2:4, 1:1.5:3 and 1:1:2 were produced and cured for 7 days, 21 days and 28 days at water to cement ratio (w/c) of 0.5 and 0.6 respectively. Flow, bond strength, and flexural tests were conducted on the samples. The highest bond strength was recorded for mix ratio 1:1:2 at w/c of 0.5 when tested at 28 days with a value of 5.56 N/mm2. This value is 0.072% higher than the 28th day strength of 5.52 N/mm2 for SCC without replacement of the granite content. Also, the highest flexural strength was recorded for mix ratio 1:1:2 at w/c of 0.5 when tested at 28 days with a value of 6.88 N/mm2. It was concluded that palm kernel shell can be safely used for partial replacement in SCC.


2013 ◽  
Vol 12 (7) ◽  
pp. 451-459
Author(s):  
Ashraf Yehia El-Naggar ◽  
Mohamed A. Ebiad

Gasoline come primarily from petroleum cuts, it is the preferred liquid fuel in our lives. Two gasoline samples of octane numbers 91 and 95 from Saudi Arabia petrol stations were studied. This study was achieved at three different temperatures 20oC, 30oC and 50oC representing the change in temperatures of the different seasons of the year. Both the evaporated gases of light aromatic hydrocarbons (BTEX) of gasoline samples inside the tank were subjected to analyze qualitatively and quantitatively via capillary gas chromatography. The detailed hydrocarbon composition and the octane number of the studied gasoline samples were determined using detailed hydrocarbon analyzer. The idea of research is indicating the impact of light aromatic compounds in gasoline on the toxic effect of human and environment on the one hand, and on octane number of gasoline on the other hand. Although the value of octane number will be reduced but this will have a positive impact on the environment as a way to produce clean fuel.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aiyan Guan ◽  
Inge Van Damme ◽  
Frank Devlieghere ◽  
Sarah Gabriël

AbstractAnisakidae, marine nematodes, are underrecognized fish-borne zoonotic parasites. Studies on factors that could trigger parasites to actively migrate out of the fish are very limited. The objective of this study was to assess the impact of different environmental conditions (temperature, CO2 and O2) on larval motility (in situ movement) and mobility (migration) in vitro. Larvae were collected by candling or enzymatic digestion from infected fish, identified morphologically and confirmed molecularly. Individual larvae were transferred to a semi-solid Phosphate Buffered Saline agar, and subjected to different temperatures (6 ℃, 12 ℃, 22 ℃, 37 ℃) at air conditions. Moreover, different combinations of CO2 and O2 with N2 as filler were tested, at both 6 °C and 12 °C. Video recordings of larvae were translated into scores for larval motility and mobility. Results showed that temperature had significant influence on larval movements, with the highest motility and mobility observed at 22 ℃ for Anisakis spp. larvae and 37 ℃ for Pseudoterranova spp. larvae. During the first 10 min, the median migration of Anisakis spp. larvae was 10 cm at 22 ℃, and the median migration of Pseudoterranova spp. larvae was 3 cm at 37 ℃. Larval mobility was not significantly different under the different CO2 or O2 conditions at 6 °C and 12 ℃. It was concluded that temperature significantly facilitated larval movement with the optimum temperature being different for Anisakis spp. and Pseudoterranova spp., while CO2 and O2 did not on the short term. This should be further validated in parasite-infected/spiked fish fillets.


2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Hadi Torkamani ◽  
Shahram Raygan ◽  
Carlos Garcia Mateo ◽  
Yahya Palizdar ◽  
Jafar Rassizadehghani ◽  
...  

AbstractIn this study, dual-phase (DP, ferrite + martensite) microstructures were obtained by performing intercritical heat treatments (IHT) at 750 and 800 °C followed by quenching. Decreasing the IHT temperature from 800 to 750 °C leads to: (i) a decrease in the volume fraction of austenite (martensite after quenching) from 0.68 to 0.36; (ii) ~ 100 °C decrease in martensite start temperature (Ms), mainly due to the higher carbon content of austenite and its smaller grains at 750 °C; (iii) a reduction in the block size of martensite from 1.9 to 1.2 μm as measured by EBSD. Having a higher carbon content and a finer block size, the localized microhardness of martensite islands increases from 380 HV (800 °C) to 504 HV (750 °C). Moreover, despite the different volume fractions of martensite obtained in DP microstructures, the hardness of the steels remained unchanged by changing the IHT temperature (~ 234 to 238 HV). Applying lower IHT temperature (lower fraction of martensite), the impact energy even decreased from 12 to 9 J due to the brittleness of the martensite phase. The results of the tensile tests indicate that by increasing the IHT temperature, the yield and ultimate tensile strengths of the DP steel increase from 493 to 770 MPa, and from 908 to 1080 MPa, respectively, while the total elongation decreases from 9.8 to 4.5%. In contrast to the normalized sample, formation of martensite in the DP steels could eliminate the yield point phenomenon in the tensile curves, as it generates free dislocations in adjacent ferrite.


Author(s):  
Zahid Iqbal Khan ◽  
Zurina Binti Mohamad ◽  
Abdul Razak Bin Rahmat ◽  
Unsia Habib ◽  
Nur Amira Sahirah Binti Abdullah

This work explores a novel blend of recycled polyethylene terephthalate/polyamide 11 (rPET/PA11). The blend of rPET/PA11 was introduced to enhance the mechanical properties of rPET at various ratios. The work’s main advantage was to utilize rPET in thermoplastic form for various applications. Three different ratios, i.e. 10, 20 and 30 wt.% of PA11 blend samples, were prepared using a twin-screw extruder and injection moulding machine. The mechanical properties were examined in terms of tensile, flexural and impact strength. The tensile strength of rPET was improved more than 50%, while the increase in tensile strain was observed 42.5% with the addition of 20 wt.% of PA11. The improved properties of the blend were also confirmed by the flexural strength of the blends. The flexural strength was increased from 27.9 MPa to 48 MPa with the addition of 30 wt.% PA11. The flexural strain of rPET was found to be 1.1%. However, with the addition of 10, 20 and 30 wt.% of PA11, the flexural strain was noticed as 1.7, 2.1, and 3.9% respectively. The impact strength of rPET/PA11 at 20 wt.% PA11 was upsurged from 110.53 to 147.12 J/m. Scanning electron microscopy analysis revealed a dispersed PA11 domain in a continuous rPET matrix morphology of the blends. This work practical implication would lead to utilization of rPET in automobile, packaging, and various industries.


2021 ◽  
pp. 002199832199945
Author(s):  
Jong H Eun ◽  
Bo K Choi ◽  
Sun M Sung ◽  
Min S Kim ◽  
Joon S Lee

In this study, carbon/epoxy composites were manufactured by coating with a polyamide at different weight percentages (5 wt.%, 10 wt.%, 15 wt.%, and 20 wt.%) to improve their impact resistance and fracture toughness. The chemical reaction between the polyamide and epoxy resin were examined by fourier transform infrared spectroscopy, differential scanning calorimetry and X-ray photoelectron spectroscopy. The mechanical properties and fracture toughness of the carbon/epoxy composites were analyzed. The mechanical properties of the carbon/epoxy composites, such as transverse flexural tests, longitudinal flexural tests, and impact tests, were investigated. After the impact tests, an ultrasonic C-scan was performed to reveal the internal damage area. The interlaminar fracture toughness of the carbon/epoxy composites was measured using a mode I test. The critical energy release rates were increased by 77% compared to the virgin carbon/epoxy composites. The surface morphology of the fractured surface was observed. The toughening mechanism of the carbon/epoxy composites was suggested based on the confirmed experimental data.


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