scholarly journals Mechanical Modification of Nanomaterials on Fully Saturated Concrete in Groundwater Reservoir Under Long-Term Water Immersion

2021 ◽  
Vol 8 ◽  
Author(s):  
XianJie Hao ◽  
Yingnan Wei ◽  
Zeyu Chen ◽  
Honglan Zhang ◽  
Yifan Niu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Water Immersion ◽  
Deformation Modulus ◽  
Concrete Sample ◽  
Hydraulic Structures ◽  
Safe Operation ◽  
Modifying Effect ◽  
Series Of Experiments ◽  
Saturated Concrete

With the increasing number of hydraulic structures in service, many scholars have investigated the performance of saturated concrete, however, there are few studies on the influences of different contents and types of nanomaterials on the performance of fully saturated concrete. In this paper, a series of experiments on concrete with different contents of nano SiO2, nano Al2O3 and nano TiO2 are performed, such as electron mirror scanning, uniaxial compression, acoustic emission, etc., and the microstructure, mechanical properties of samples are compared and analyzed. The results show that: 1) By the addition of various kinds of nanomaterials to saturated concrete, the microstructure of saturated concrete is significantly improved, and the compactness and integrity of the slurry are improved 2) The mechanical properties of saturated concrete are significantly improved by the addition of 3 wt% nanomaterials. And the compressive strength of the saturated concrete sample containing 3 wt% nano-Al2O3 is the largest and the deformation modulus of the saturated concrete sample containing 6 wt% nano-Al2O3 is the largest. 3) Compared with dry concrete, when the concrete is saturated, the modifying effect of nanomaterials on the mechanical properties of concrete is weakened. The results of this study have important guiding significance for the study of the nano-modification and the safe operation of hydraulic structures.

scholarly journals A More Realistic Study on the Mechanical Properties of CFRC Composite Grouting Material under a Long-Term Water Immersion Process

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Yao Xiao ◽  
Huafeng Deng ◽  
Jianlin Li ◽  
Eleyas Assefa
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Carbon Fiber ◽  
Water Immersion ◽  
Fiber Content ◽  
Grouting Material ◽  
Bonding Properties ◽  
Grouting Materials ◽  
Dam Foundations

The long-term effect of water immersion on the mechanical properties of CFRC composite grouting materials was studied by using five different carbon fiber contents (0, 0.25%, 0.50%, 0.75%, and 1.00%). The direct shear and long-term immersion tests were performed based on the specified and optimum values of carbon fiber content, respectively. The results showed the following: (1) the application of carbon fiber significantly improved the shear resistance of CRFC composite grouting material by using “reinforcing” and “anchoring” actions. The shear strength of the specimen was increasing by 5.66%∼43.41% when the carbon fiber content increased from 0.25% to 1.00%. After a comprehensive analysis, the optimum carbon fiber content was found to be 0.75%. (2) The degradation in the compressive and tensile strength of CRFC composite specimens exhibited a consistent trend (i.e., a steep gradient was gradually followed by a gentle slope) under a long-term water immersion process. About 90% of the total degradation in the compressive and tensile strength has occurred in 90 immersion days (i.e., 16.05% and 18.45%, respectively). In comparison, the degradation in the tensile strength (20.05%) was slightly higher than the compressive strength (18.16%). (3) Under the long-term water immersion process: the properties of the specimens were gradually deteriorating, the carbon fibers were gradually reaching a fatigue stage, and the bonding properties of carbon fiber was decreasing, which resulted in a reduction in the compressive and tensile strength. The uniaxial compression failure mode changed from brittle to ductile, and the development of local failure was very noticeable. Based on the findings of this paper, groundwater has a significant impact on the mechanical properties of grouted rock mass such as dam foundations and abutments. Therefore, the degradation in the grouting materials has to be considered in practical cases.

scholarly journals Impact strength of denture base and reline acrylic resins subjected to long-term water immersion

2011 ◽  
Vol 22 (1) ◽  
pp. 56-61 ◽  
Author(s):  
Amanda Fucci Wady ◽  
Ana Lucia Machado ◽  
Carlos Eduardo Vergani ◽  
Ana Cláudia Pavarina ◽  
Eunice Teresinha Giampaolo
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Water Immersion ◽  
Water Storage ◽  
Charpy Impact ◽  
Denture Base ◽  
Effect Of Water ◽  
Acrylic Resins ◽  
The Impact

Water may influence the mechanical properties of the acrylic resins. Thus, the effect of water storage on the impact strength (IS) of one denture base (Lucitone 550 - L) and four reline resins (Tokuyama Rebase II - T; UfiGel Hard - U; Kooliner - K; New Truliner - NT) was evaluated. Bars of L were made (60 x 6 x 2 mm) and relined (2 mm) with T, U, K, NT and L. Intact specimens of each material (60 x 6 x 4 mm) were also fabricated for comparative purposes. Specimens were submitted to Charpy impact tests without water storage (control) and after immersion in water for 7, 90 and 180 days. Data (kJ/m²) analyzed by two-way ANOVA and Tukey's test (p=0.05) revealed that after 90 days, U exhibited an increase in the IS (0.93) compared to 7 days (0.58). K (1.48) and L/K (7.21) exhibited a decrease at the 7-day period (1.01 and 3.23, respectively). NT (0.60) showed an increase in the IS after 180 days (1.52), whereas L/NT (7.70) showed a decrease (3.17). Water immersion improved the IS of U and NT, and decreased the IS of K, L/K, and L/NT. Water may affect differently the IS of acrylic resins and, consequently, the resistance to fracture of relined denture bases.

Durability study of pultruded carbon fiber reinforced polymer plates subjected to water immersion

2017 ◽  
Vol 21 (4) ◽  
pp. 571-579 ◽  
Author(s):  
Bin Hong ◽  
Guijun Xian ◽  
Zike Wang
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Water Immersion ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Resin Matrix ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

Pultruded carbon fiber reinforced polymer plates have been widely used for structural rehabilitation due to their excellent mechanical properties. Even though, the long-term durability performance of carbon fiber reinforced polymer plates is still a concern, especially when subjected to harsh environmental conditions (e.g. water immersion). In the present study, the effects of water immersion at 23°C, 40°C, and 60°C on the degradation of the pultruded carbon fiber reinforced polymer plates were investigated in terms of water uptake and mechanical properties. To elucidate the degradation mechanisms, the resin matrix and the fiber and resin adhesion were also assessed in the same conditions. The test results indicated that water immersion, especially at higher temperatures, leads to serious fiber debonding, and thus the carbon fiber reinforced polymer samples absorb much more water than the resin matrix. In addition, the transverse flexural strength of the carbon fiber reinforced polymer plates, closely correlated to the fiber–resin adhesion, reduced significantly at high temperatures. On the contrary, the resin matrix and carbon fiber reinforced polymer plates show much less degradation subjected to the same immersion conditions. Therefore, to comprehensively understand the long-term durability of a carbon fiber reinforced polymer material, it is necessary to test the variation of the bonding strength between fiber and resin matrix, in addition to the tensile performances in fiber directions of the carbon fiber reinforced polymer plates.

scholarly journals Effect of long-term water immersion or thermal shock on mechanical properties of high-impact acrylic denture base resins

2016 ◽  
Vol 35 (2) ◽  
pp. 204-209 ◽  
Author(s):  
Hirono SASAKI ◽  
Ippei HAMANAKA ◽  
Yutaka TAKAHASHI ◽  
Tomohiro KAWAGUCHI
Keyword(s):  
Mechanical Properties ◽  
Thermal Shock ◽  
Water Immersion ◽  
High Impact ◽  
Denture Base

scholarly journals Mechanical Properties of Cement-Treated Soil Mixed with Cellulose Nanofibre

2021 ◽  
Vol 11 (14) ◽  
pp. 6425
Author(s):  
Hidenori Takahashi ◽  
Shinya Omori ◽  
Hideyuki Asada ◽  
Hirofumi Fukawa ◽  
Yusuke Gotoh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Geotechnical Engineering ◽  
Strength Development ◽  
Soft Ground ◽  
Wood Cellulose ◽  
Treated Soil ◽  
Made In ◽  
Cement Treatment

Cellulose nanofibre (CNF), a material composed of ultrafine fibres of wood cellulose fibrillated to nano-order level, is expected to be widely used because of its excellent properties. However, in the field of geotechnical engineering, almost no progress has been made in the development of techniques for using CNFs. The authors have focused on the use of CNF as an additive in cement treatment for soft ground, where cement is added to solidify the ground, because CNF can reduce the problems associated with cement-treated soil. This paper presents the results of a study on the method of mixing CNF, the strength and its variation obtained by adding CNF, and the change in permeability. CNF had the effect of mixing the cement evenly and reducing the variation in the strength of the treated soil. The CNF mixture increased the strength at the initial age but reduced the strength development in the long term. The addition of CNF also increased the flexural strength, although it hardly changed the permeability.

scholarly journals High-strength and fibrous capsule–resistant zwitterionic elastomers

2021 ◽  
Vol 7 (1) ◽  
pp. eabc5442
Author(s):  
Dianyu Dong ◽  
Caroline Tsao ◽  
Hsiang-Chieh Hung ◽  
Fanglian Yao ◽  
Chenjue Tang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Strength ◽  
High Strength ◽  
Design Principles ◽  
Fibrous Capsule ◽  
High Mechanical Strength ◽  
Capsule Formation ◽  
Locking Mechanism ◽  
Fibrous Capsule Formation

The high mechanical strength and long-term resistance to the fibrous capsule formation are two major challenges for implantable materials. Unfortunately, these two distinct properties do not come together and instead compromise each other. Here, we report a unique class of materials by integrating two weak zwitterionic hydrogels into an elastomer-like high-strength pure zwitterionic hydrogel via a “swelling” and “locking” mechanism. These zwitterionic-elastomeric-networked (ZEN) hydrogels are further shown to efficaciously resist the fibrous capsule formation upon implantation in mice for up to 1 year. Such materials with both high mechanical properties and long-term fibrous capsule resistance have never been achieved before. This work not only demonstrates a class of durable and fibrous capsule–resistant materials but also provides design principles for zwitterionic elastomeric hydrogels.

scholarly journals Effect of Water Ingress on the Mechanical and Chemical Properties of Polybutylene Terephthalate Reinforced with Glass Fibers

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1261
Author(s):  
Catarina S. P. Borges ◽  
Alireza Akhavan-Safar ◽  
Eduardo A. S. Marques ◽  
Ricardo J. C. Carbas ◽  
Christoph Ueffing ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Water Uptake ◽  
Significant Influence ◽  
Water Immersion ◽  
Water Diffusion ◽  
Polybutylene Terephthalate ◽  
Chemical Changes ◽  
Water Ingress ◽  
Effect Of Water

Short fiber reinforced polymers are widely used in the construction of electronic housings, where they are often exposed to harsh environmental conditions. The main purpose of this work is the in-depth study and characterization of the water uptake behavior of PBT-GF30 (polybutylene terephthalate with 30% of short glass fiber)as well as its consequent effect on the mechanical properties of the material. Further analysis was conducted to determine at which temperature range PBT-GF30 starts experiencing chemical changes. The influence of testing procedures and conditions on the evaluation of these effects was analyzed, also drawing comparisons with previous studies. The water absorption behavior was studied through gravimetric tests at 35, 70, and 130 °C. Fiber-free PBT was also studied at 35 °C for comparison purposes. The effect of water and temperature on the mechanical properties was analyzed through bulk tensile tests. The material was tested for the three temperatures in the as-supplied state (without drying or aging). Afterwards, PBT-GF30 was tested at room temperature following water immersion at the three temperatures. Chemical changes in the material were also analyzed through Fourier-transform infrared spectroscopy (FTIR). It was concluded that the water diffusion behavior is Fickian and that PBT absorbs more water than PBT-GF30 but at a slightly higher rate. However, temperature was found to have a more significant influence on the rate of water diffusion of PBT-GF30 than fiber content did. Temperature has a significant influence on the mechanical properties of the material. Humidity contributes to a slight drop in stiffness and strength, not showing a clear dependence on water uptake. This decrease in mechanical properties occurs due to the relaxation of the polymeric chain promoted by water ingress. Between 80 and 85 °C, after water immersion, the FTIR profile of the material changes, which suggests chemical changes in the PBT. The water absorption was simulated through heat transfer analogy with good results. From the developed numerical simulation, the minimum plate size to maintain the water ingress unidirectional was 30 mm, which was validated experimentally.

Sign in / Sign up

Export Citation Format

Share Document