scholarly journals Studies on Impact Resistance of Self-Compacting Concrete with mechanically treated Recycled Coarse Aggregate

2021 ◽  
Vol 1197 (1) ◽  
pp. 012051
Author(s):  
Srikanth Nune ◽  
N R Dakshina Murthy ◽  
M V Seshagiri Rao
Keyword(s):  
Impact Energy ◽  
Coefficient Of Variation ◽  
Coarse Aggregate ◽  
Fine Particles ◽  
Impact Resistance ◽  
Replacement Level ◽  
Self Compacting Concrete ◽  
Conventional Concrete ◽  
Recycled Coarse Aggregate ◽  
The Impact

Abstract Self-compacting concrete (SCC) is an extraordinary type of concrete that is extremely flowable and spreads into the formwork without the need of external vibration. In order to attain self-compatibility SCC obliges extensively surplus quantity of fine particles as compared to conventional concrete. Recycled Coarse Aggregate (RCA) obtained by crushing of old concrete is used in the investigational analysis. Nan-Su method is used to design the SCC mixes A and B (M35 and M45). The current experimental study aims to evaluate the impact energy of Recycled Coarse Aggregate (RCA) based self- compacting concrete by replacing with Natural Coarse Aggregate (NCA) (25%, 50%, 75%, and 100%) in unprocessed and processed states for various number of revolutions (500R, 1000R, 1500R, 2000R). Tests were carried out with a constant mass of hammer (16.38 kg). The impact energy determined for the Mixes A and B is compared with respect to replacement level and processing of RCA. The impact energy calculated is maximum for mix-A (1500 and 2000 revolutions) and mix-B (2000 revolutions) at 75% and 100% replacement of RCA respectively. From the experimental results of obtained Coefficient of Variation (CoV) with respect to processing of aggregate, in both the mixes it is observed that RCA in unprocessed state and processed state (1500R) has good Coefficient of Variation. Comparing the results of Coefficient of Variation with respect to replacement level of aggregate it has a very good CoV at 25% replacement level of RCA for both the mixes.

scholarly journals The Effect of Styrofoam Artificial Lightweight Aggregate (ALWA) on Compressive Strength of Self Compacting Concrete (SCC)

2018 ◽  
Vol 4 (9) ◽  
pp. 2111 ◽  
Author(s):  
Dhiafah Hera Darayani ◽  
Tavio Tavio ◽  
I G. P. Raka ◽  
Puryanto Puryanto
Keyword(s):  
Compressive Strength ◽  
Modulus Of Elasticity ◽  
Coarse Aggregate ◽  
Lightweight Aggregate ◽  
Structural Members ◽  
Self Compacting Concrete ◽  
Conventional Concrete ◽  
Concrete Material ◽  
Compressive Strength Test ◽  
The Impact

Self-compacting concrete (SCC) is a fresh concrete that is able to flow and fill up the formwork by itself without the need of a vibrator to compact it. One of the reasons that causes the damage of a building structure during an earthquake is the heavy weight of its structural members which are from the high density of the material used such concrete material. Lightweight aggregate is one of the solutions to reduce the weight of the structure. Therefore, the SCC using the artificial lightweight aggregate (ALWA) is one of the solutions to reduce the self-weight (dead load) of a structure. This research was conducted to investigate the impact of the use of ALWA in conventional concrete and SCC in terms of its compressive strength and modulus of elasticity. To study the impact of the use of ALWA in SCC, several variation of percentage of ALWA as a substitution to the natural coarse aggregate was examined. The proportions of ALWA as a replacement to the coarse aggregate were 0%, 15%, 50%, and 100%. The test specimens were the cylindrical concrete of 200 mm in height and 100 mm in diameter for both compressive strength and modulus of elasticity tests. The results of the compressive strength test indicated that the higher the percentage of ALWA used in SCC, the lower the compressive strength of the concrete. The addition of ALWA as a substitution to the natural coarse aggregate to conventional concrete and SCC was found optimum at 15% replacement with the compressive strength of conventional concrete and SCC of 21.13 and 28.33 MPa, respectively. Whereas, the modulus of elasticity of the conventional concrete and SCC were found to be 20,843.99 and 23,717.77 MPa, respectively.

scholarly journals Effect of Recycled Coarse Aggregate and Bagasse Ash on Two-Stage Concrete

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 556
Author(s):  
Muhammad Faisal Javed ◽  
Afaq Ahmad Durrani ◽  
Sardar Kashif Ur Rehman ◽  
Fahid Aslam ◽  
Hisham Alabduljabbar ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Construction Material ◽  
Strength Reduction ◽  
Recycled Aggregate ◽  
Two Stage ◽  
Conventional Concrete ◽  
Recycled Coarse Aggregate ◽  
Coarse Aggregates

Numerous research studies have been conducted to improve the weak properties of recycled aggregate as a construction material over the last few decades. In two-stage concrete (TSC), coarse aggregates are placed in formwork, and then grout is injected with high pressure to fill up the voids between the coarse aggregates. In this experimental research, TSC was made with 100% recycled coarse aggregate (RCA). Ten percent and twenty percent bagasse ash was used as a fractional substitution of cement along with the RCA. Conventional concrete with 100% natural coarse aggregate (NCA) and 100% RCA was made to determine compressive strength only. Compressive strength reduction in the TSC was 14.36% when 100% RCA was used. Tensile strength in the TSC decreased when 100% RCA was used. The increase in compressive strength was 8.47% when 20% bagasse ash was used compared to the TSC mix that had 100% RCA. The compressive strength of the TSC at 250 °C was also determined to find the reduction in strength at high temperature. Moreover, the compressive and tensile strength of the TSC that had RCA was improved by the addition of bagasse ash.

scholarly journals Impact resistance of steel materials to ballistic ejecta and shelter development using steel deck plates

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Hiroyuki Yamada ◽  
Kohei Tateyama ◽  
Shino Naruke ◽  
Hisashi Sasaki ◽  
Shinichi Torigata ◽  
...  
Keyword(s):  
Impact Energy ◽  
Impact Test ◽  
Impact Resistance ◽  
Protective Layer ◽  
High Strength ◽  
Steel Plates ◽  
Corrugated Plates ◽  
Shelter Construction ◽  
The Impact ◽  
Ballistic Ejecta

AbstractThe destruction caused by ballistic ejecta from the phreatic eruptions of Mt. Ontake in 2014 and Mt. Kusatsu-Shirane (Mt. Moto-Shirane) in 2018 in Japan, which resulted in numerous casualties, highlighted the need for better evacuation facilities. In response, some mountain huts were reinforced with aramid fabric to convert them into shelters. However, a number of decisions must be made when working to increase the number of shelters, which depend on the location where they are to be built. In this study, we propose a method of using high-strength steel to reinforce wooden buildings for use as shelters. More specifically, assuming that ballistic ejecta has an impact energy of 9 kJ or more, as in previous studies, we developed a method that utilizes SUS304 and SS400 unprocessed steel plates based on existing impact test data. We found that SUS304 is particularly suitable for use as a reinforcing material because it has excellent impact energy absorption characteristics due to its high ductility as well as excellent corrosion resistance. With the aim of increasing the structural strength of steel shelters, we also conducted an impact test on a shelter fabricated from SS400 deck plates (i.e., steel with improved flexural strength provided by work-hardened trapezoidal corrugated plates). The results show that the shelter could withstand impact with an energy of 13.5 kJ (2.66 kg of simulated ballistic ejecta at 101 m/s on impact). In addition, from the result of the impact test using the roof-simulating structure, it was confirmed the impact absorption energy is further increased when artificial pumice as an additional protective layer is installed on this structure. Observations of the shelter after the impact test show that there is still some allowance for deformation caused by projectile impact, which means that the proposed steel shelter holds promise, not only structurally, but also from the aspects of transportation and assembly. Hence, the usefulness of shelters that use steel was shown experimentally. However, shelter construction should be suitable for the target environment.

Interplay of fabric structure and shear thickening fluid impregnation in moderating the impact response of high-performance woven fabrics

2020 ◽  
Vol 54 (28) ◽  
pp. 4387-4395
Author(s):  
Sanchi Arora ◽  
Abhijit Majumdar ◽  
Bhupendra Singh Butola
Keyword(s):  
Beneficial Effect ◽  
Energy Absorption ◽  
Impact Energy ◽  
High Performance ◽  
Research Work ◽  
Impact Resistance ◽  
Woven Fabrics ◽  
Woven Fabric ◽  
Fabric Structure ◽  
The Impact

The beneficial effect of STF impregnation in enhancing the impact resistance of high-performance fabrics has been extensively reported in the literature. However, this research work reports that fabric structure has a decisive role in moderating the effectiveness of STF impregnation in terms of impact energy absorption. Plain woven fabrics having sett varying from 25 × 25 inch−1 to 55 × 55 inch−1 were impregnated with STF at two different padding pressures to obtain different add-ons. The impact energy absorption by STF impregnated loosely woven fabrics was found to be higher than that of their neat counterparts for both levels of add-on, while opposite trend was observed in case of tightly woven fabrics. Further, comparison of tightly woven plain, 2/2 twill, 3/1 twill and 2 × 2 matt fabrics revealed beneficial effect of STF impregnation, except for the plain woven fabric, establishing that there exists a fabric structure-STF impregnation interplay that tunes the impact resistance of woven fabrics.

Experimental Study on Flexural Behaviors of Steel Reinforced Recycled Coarse Aggregate Concrete Beams

2012 ◽  
Vol 166-169 ◽  
pp. 1614-1619 ◽  
Author(s):  
Wen Yue Qin ◽  
Yu Liang Chen ◽  
Zong Ping Chen
Keyword(s):  
Bearing Capacity ◽  
Coarse Aggregate ◽  
Concrete Beams ◽  
Concrete Strength ◽  
Recycled Concrete ◽  
Flexural Behavior ◽  
Aggregate Concrete ◽  
Strength Grade ◽  
Recycled Coarse Aggregate ◽  
The Impact

In order to reveal the flexural behavior of normal section of steel reinforced recycled coarse aggregate concrete beams，6 steel reinforced recycled concrete beams were designed for flexural test，the study mainly considered the impact of coarse aggregate replacement rates and concrete strength grade two changing parameters on the flexural behavior of steel reinforced recycled coarse aggregate concrete beams. Through this test, the whole mechanical process、crack distribution and failure behavior of this kind of specimens were observed, and obtained the stress-strain distribution curves、the ultimate bearing capacity and load-displacement curves parameters. Based on the study measurement data, deeply analyzed the impact of coarse aggregate replacement rates and concrete strength grade on the flexural behavior of steel reinforced recycled coarse aggregate concrete beams. The result shows that: steel reinforced recycled coarse aggregate concrete beams’ failure pattern was similar to normal SRC beams, during loading process the section strain agreed with the plane-section assumption, and the beams have good bearing capacity and deformation performance.

scholarly journals Recycled Rubber as an Aggregate Replacement in Self-Compacting Concrete—Literature Overview

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1729 ◽  
Author(s):  
Robert Bušić ◽  
Ivana Miličević ◽  
Tanja Šipoš ◽  
Kristina Strukar
Keyword(s):  
Coarse Aggregate ◽  
Impact Resistance ◽  
Ecological Problem ◽  
Self Compacting Concrete ◽  
Tire Rubber ◽  
Waste Tire ◽  
Waste Tire Rubber ◽  
Sand And Gravel ◽  
Near Future ◽  
Recycled Waste

In the past few decades, due to the exponential increase of the world’s population, the number of discarded waste tires has become a serious ecological and environmental problem. Decomposition of waste tire rubber can take longer than 50 years, and every year the number of discarded tires is rapidly growing. With the inclusion of waste tire rubber into self-compacting concrete this global problem can be reduced. Waste tire rubber can be incorporated in self-compacting concrete by partially replacing the natural fine and coarse aggregate, reducing consumption of sand and gravel and preserving these natural materials. In addition, recycling and reusing waste tire rubber avoids the need for tire landfilling, as one of the major ecological problem of the near future. Replacement of natural aggregate with waste tire rubber can have an undesirable influence on the mechanical properties of self-compacting concrete, i.e., compressive strength, flexural strength, splitting tensile strength, and modulus of elasticity, however. On the other hand, replacing natural gravel or sand with waste tire rubber can improve impact resistance, ductility, and fatigue resistance. This paper presents an overview of the literature investigating recycled waste tire rubber used as a fine and/or coarse aggregate replacement in self-compacting concrete and its influence on several essential fresh and hardened self-compacting concrete properties.

Experimental Studies on Basic Performance and Application of Self-Compacting Concrete Using Waste Brick Recycled Coarse Aggregate

2014 ◽  
Vol 955-959 ◽  
pp. 2658-2662
Author(s):  
Ying Li Liu ◽  
Han Qing Liu ◽  
Lin Gao
Keyword(s):  
Rural Areas ◽  
Coarse Aggregate ◽  
Experimental Studies ◽  
Green Building ◽  
Recycled Concrete ◽  
Clay Brick ◽  
Self Compacting Concrete ◽  
Aggregate Gradation ◽  
Construction Waste ◽  
Recycled Coarse Aggregate

With rapid economic development in China, the frequency of that new buildings replace old buildings increases gradually in rural areas, which inevitably results in the emergence of a large amount of waste clay brick. The processing of construction waste takes up a lot of land resources and worsen the existing rural environmental pollution situation. using waste clay brick to prepare recycled coarse aggregate concrete not only can effectively eliminate construction waste and reduce the consumption of original coarse aggregate and thus the cost of buildings, but also solves a series of environmental problems—it conforms to the concept of "green building" and stands in line with the strategic objectives of sustainable development. This paper researched on the influence of recycled coarse aggregate gradation and water cement ratio to the strength of recycled concrete at first, then experimentally verified the application feasibility of recycled coarse aggregate self-compacting concrete.

Impact resistance of Nomex honeycomb sandwich structures with thin fibre reinforced polymer facesheets

2016 ◽  
Vol 20 (5) ◽  
pp. 531-552 ◽  
Author(s):  
Longquan Liu ◽  
Han Feng ◽  
Huaqing Tang ◽  
Zhongwei Guan
Keyword(s):  
Finite Element ◽  
Impact Energy ◽  
Sandwich Structures ◽  
Impact Resistance ◽  
Impact Response ◽  
Woven Fabric ◽  
Drop Weight ◽  
Honeycomb Sandwich ◽  
Nomex Honeycomb ◽  
The Impact

In order to investigate the impact resistance of the Nomex honeycomb sandwich structures skinned with thin fibre reinforced woven fabric composites, both drop-weight experimental work and meso-mechanical finite element modelling were conducted and the corresponding output was compared. Drop-weight impact tests with different impact parameters, including impact energy, impactor mass and facesheets, were carried out on Nomex honeycomb-cored sandwich structures. It was found that the impact resistance and the penetration depth of the Nomex honeycomb sandwich structures were significantly influenced by the impact energy. However, for impact energies that cause full perforation, the impact resistance is characterized with almost the same initial stiffness and peak force. The impactor mass has little influence on the impact response and the perforation force is primarily dependent on the thickness of the facesheet, which generally varies linearly with it. In the numerical simulation, a comprehensive finite element model was developed which considers all the constituent materials of the Nomex honeycomb, i.e. aramid paper, phenolic resin, and the micro-structure of the honeycomb wall. The model was validated against the corresponding experimental results and then further applied to study the effects of various impact angles on the response of the honeycomb. It was found that both the impact resistance and the perforation depth are significantly influenced by the impact angle. The former increases with the obliquity, while the latter decreases with it. The orientation of the Nomex core has little effect on the impact response, while the angle between the impact direction and the fibre direction of the facesheets has a great influence on the impact response.

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