scholarly journals BEHAVIOUR OF TERNARY BLENDED CEMENT CONCRETE SLAB WITH STEEL FIBER UNDER IMPACT LOADING

2021 ◽  
pp. 82-94
Author(s):  
Chandrasekaran Vijayvenkatesh ◽  
Reddy Rajupalem Rahul
Keyword(s):  
Crack Resistance ◽  
Impact Loading ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Impact Load ◽  
Concrete Slab ◽  
Blended Cement ◽  
Cement Concrete ◽  
Reinforced Concrete Slabs ◽  
The Impact

Statement of the problem. An experimental investigation of impact strength of ternary blended cement concrete slab with steel fiber under impact loading was carried out. The amount of replacement of binder with Fly ash varies from 10 to 30 % in step of 10 %, glass powder from 20 to 40 % in step of 10 % and fiber volume fraction from 0.75 to 2.25 % in step of 0.75 %. Parametric performance of ten 600 × 600 mm, 60 mm thick reinforced concrete slabs was evaluated. The impact test on the slab was conducted by dropping a steel ball from a height of 457 mm under impact setup. The parameters like failure mode, the impact energy of first crack and ultimate crack failure, ductility index, failure pattern, ultimate crack resistance, crack resistance ratio were investigated when subjected to impact load. Results. The test results reported that the slab specimen S7 shows better performance in strength.

THE EFFECT OF IMPACT LOADS ON PRESTRESSED CONCRETE SLABS

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Youmn Al Rawi ◽  
Yehya Temsah ◽  
Hassan Ghanem ◽  
Ali Jahami ◽  
Mohamad Elani
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Impact Loading ◽  
Concrete Slab ◽  
Concrete Slabs ◽  
Shear Mode ◽  
Reinforced Concrete Slab ◽  
Finite Element Program ◽  
Reinforced Concrete Slabs ◽  
The Impact

Many research studies have been conducted on the effect of impact loading on structures, and design procedures were proposed for reinforced concrete (RC) slabs; however the availability of these studies and procedures are limited for prestressed slabs. The proposed research will examine, using numerical analysis, the impact of rock fall on prestressed concrete slabs with equivalent moment capacity reinforced concrete slabs. It is expected that prestressed concrete slabs will have different behavior to resist impact loading compared with traditional reinforced concrete slabs. The thickness of the prestressed concrete slab will be 25cm whereas that of the reinforced concrete slab will be 30cm. The impact loading consists of 500Kg drop weight. The drop height will be 10m, 15m and 20m.The structural analysis is performed using a Finite Element program "ABAQUS". A comparison will be done between both slab types in terms of failure mode, damage, and deflection. It has been found that both slabs failed in punching. However, the RC slab performed better than the prestressed concrete slab with respect to the value of the deflection at mid-span, while both showed punching shear mode of failure.

BEHAVIOR OF REINFORCED CONCRETE SLABS UNDER ACCIDENTAL IMPACTS

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Shamsoon Fareed
Keyword(s):  
Reinforced Concrete ◽  
Impact Loading ◽  
Concrete Slab ◽  
High Mass ◽  
Concrete Slabs ◽  
Reinforced Concrete Slab ◽  
Reinforced Concrete Slabs ◽  
Numerical Predictions ◽  
Operational Life ◽  
The Impact

Loads resulting from activities such as rock fall, heavy drop weights (for e.g. equipment's, heavy machines during installation), missile and aircraft interaction with slabs may results in loading intensity which have higher magnitude as compared to static loading. Based on the velocity of the impacting object at the time of contact, these activities may result in impact loading. Therefore, slabs designed should provide resistance to these accidental loading during their entire operational life. In this study, a dynamic non-linear finite element analyses were conducted to investigate the behavior of the reinforced concrete slabs subjected to high-mass low-velocity impacts. For this purpose, initially an already published impact test results were used to validate the numerical predictions. Following validation, a study was conducted to investigate the influence of the impact velocity on the behavior of the reinforced concrete slab. Based on the numerical investigation, it was found that the velocity of the impacting object has a significant influence on the behavior exhibited by slab under impact loading. Furthermore, it was also found that the behavior of slab under impact is both local and global. Local behavior is associated with the damage caused at the contact area of the slab and the impactor, whereas global behavior refers to the overall deformation of the slab when stress waves move away from the impact zone and travel towards the supports.

Failure Behavior of RC Slabs Subjected to Medium Velocity Impact

2016 ◽  
Author(s):  
Masuhiro Beppu ◽  
Shinnosuke Kataoka
Keyword(s):  
Shear Failure ◽  
Impact Load ◽  
Concrete Slab ◽  
Reaction Force ◽  
Plain Concrete ◽  
Concrete Specimen ◽  
Failure Behavior ◽  
Velocity Impact ◽  
Reinforced Concrete Slabs ◽  
The Impact

This study is intended to investigate failure mechanism of plain concrete and reinforced concrete slabs subjected to a medium-velocity impact by conducting impact tests. In a series of tests, a steel projectile with a mass of 8.3kg collided a concrete slab with a thickness of 18cm. In order to examine impact response of the concrete specimen, impact load and reaction force were measured. Test results revealed that the impact velocity corresponding to the scabbing limit was about 40m/s and the failure mode of the concrete specimen subjected to the medium-velocity was similar to the punching shear failure.

scholarly journals DEFORMABILITY AND CRACK RESISTANCE OF AIRFIELD SLABS

2021 ◽  
pp. 52-61
Author(s):  
M.G. Surianinov ◽  
◽  
S.P. Neutov ◽  
I.B. Korneeva ◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Crack Resistance ◽  
Steel Fiber ◽  
Concrete Slab ◽  
Crack Opening ◽  
Experimental Studies ◽  
Concrete Slabs ◽  
Reinforced Concrete Slabs ◽  
Fiber Concrete ◽  
Steel Fiber Concrete

Abstract. The results of experimental studies of deformability and crack resistance of models of airfield slabs made of reinforced concrete and steel fiber concrete are presented. Two series of plates were tested ‒ three models of reinforced concrete and three models with steel fiber added to the concrete mixture in amount of 1% of the total volume of the product. The load was applied in small steps, the instrument readings were recorded twice at each step, and the crack opening width was measured starting from the moment of the first crack formation. Dial gauges and deflectometers were used as measuring instruments. According to the normative documents acting in Ukraine, one of two possible loading schemes was considered ‒ with the loading by the concentrated force applied on the cantilever part of a plate. The plate models were tested on a specially made stand which consisted of four supporting struts connected in pairs by beams. The airfield slab was supported by the beams. The load was applied along the width of the plate in steps ‒ 0.05 of the destructive load, along two concentrated vertical strips. Each degree of load ended with a five-minute dwell time, at the beginning and end of which readings were taken on the measuring instruments. The deformations at the same levels were measured with dial gauges. The process of crack formation was observed with a Brinell tube in the places of the greatest crack opening. It follows from the obtained results that the process of cracking in the fiber concrete slab begins at higher loads than in the reinforced concrete slab. The final and initial crack opening widths of all cracks in the fiber concrete slab are significantly lower than in the reinforced concrete slab. The deformations in steel-fiber concrete slabs during the application of load in the cantilever part, both for compressed and stretched fibers are higher than in reinforced concrete slabs. At the initial stages of load application in the cantilevered part of the slabs, the deflections increase in a linear relationship. The curves get non-linear character for airfield slabs made of reinforced concrete when the load reaches the level of 10÷25 kN, for steel-fiber-concrete slabs ‒ 15÷30 kN. In reinforced concrete slabs, the non-linearity starts a little earlier and is expressed more clearly. Experimental studies show that dispersed reinforcement of airfield slabs with steel fiber leads to their higher crack resistance.

Damage Behavior of Steel Fiber Reinforced and Polymer Modified Concrete under Impact Loading

2007 ◽  
Vol 348-349 ◽  
pp. 889-892 ◽  
Author(s):  
Yi Ping Liu ◽  
Li Qun Tang ◽  
Xiao Qing Huang
Keyword(s):  
Impact Loading ◽  
Damage Evolution ◽  
Steel Fiber ◽  
Split Hopkinson Pressure Bar ◽  
Early Stage ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Polymer Modified Concrete ◽  
The Impact

Damage behaviors of plain concrete (PC), steel fiber reinforced concrete (SFRC), steel fiber reinforced and polymer modified concrete (SFRPMC) are studied in this paper by use of a Split Hopkinson Pressure Bar (SHPB). Three kinds of concrete materials appear obvious strain rate strengthening effects. SFRPMC appears a better resistance and energy absorption ability. A rate-dependent damage model is suggested to depict the impact damage evolution of three kinds of materials under different impact velocities. The simulation results showed the theoretical model could well describe the dynamic behaviors of the three kinds of materials, and steel fibers attribute more to resist crack develop in early stage, “bridge effect” of steel fibers slow up the damage evolution in SFRC, with the addition of polymer, the internal structures of SFRPMC were modified, SFRPMC gains better ductility, and appears a kind of “softening effect”, which makes the damage in SFRPMC develop more slowly than that in PC and SFRC under impact loading.

Research on Impact Behavior of Reactive Powder Concrete

2010 ◽  
Vol 150-151 ◽  
pp. 779-782
Author(s):  
Qing Xin Zhao ◽  
Zhao Yang Liu ◽  
Jin Rui Zhang ◽  
Ran Ran Zhao
Keyword(s):  
Compressive Strength ◽  
Impact Toughness ◽  
Flexural Strength ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Impact Behavior ◽  
Reactive Powder Concrete ◽  
Flexural Toughness ◽  
Reactive Powder ◽  
The Impact

By means of the three-point bending impact equipment, with the measurement of ultrasonic velocity, the impact behavior and damage evolution of reactive powder concrete (RPC) with 0, 1%, 2% and 3% volume fraction of steel fiber were tested. The results showed that steel fiber significantly improved the compressive strength, flexural strength, flexural toughness and impact toughness of RPC matrix. The compressive strength, flexural strength, flexural toughness of RPC with 3% steel fiber increased by 40.1%, 102.1%, and 37.4 times than that of plain concrete, respectively, and simultaneously, the impact toughness of RPC with 3% steel fiber was 93.2 times higher than that with 1% steel fiber. RPC with 2% and 3% steel fiber dosage both had relatively high compressive strength, flexural strength and flexural toughness; however, compared with the sample with 2% steel fiber dosage, the impact toughness of RPC with 3% steel fiber dosage increased by more than 10 times. Therefore, taking economy and applicability into consideration, if we mainly emphasis on the compressive strength, flexural strength and flexural toughness, RPC with 2% steel fiber is optimal. While if impact toughness is critical, RPC with 3% steel fiber would be the best choice.

Influence of Crumb Rubber on Impact Energy of Steel Fiber Concrete Beams

2015 ◽  
Vol 802 ◽  
pp. 196-201
Author(s):  
Ahmed Tareq Noaman ◽  
Badorul Hisham Abu Bakar ◽  
Hazizan Md. Akil
Keyword(s):  
Impact Energy ◽  
Steel Fiber ◽  
Concrete Beams ◽  
Impact Load ◽  
Crumb Rubber ◽  
Fine Aggregate ◽  
Low Velocity ◽  
Fiber Concrete ◽  
Steel Fiber Concrete ◽  
The Impact

This paper presents the impact energy of steel fiber concrete beams at first crack and failure with different replacement ratios of crumb rubber. The test was carried out using simple low velocity drop weight test rig for both normal concrete (NC) and steel fiber concrete (SFC). The crumb rubber with particle size of 1 – 2 mm was added with replacement ratios of 5%, 15%, and 25% by volume of fine aggregate. Six batches consisting of 6 beams (100x100x500 mm) containing 0.5% of hooked end steel fibers were tested under impact load in accordance with ACI Committee 544. The specimens were tested at the age 90 days after curing in water. The results show a reduction in the compressive strength for both NC and SFC with the incorporation of crumb rubber with greater reduction at higher crumb rubber content. However, the measured impact energy for both NC and SFC was foundincreasing with the crumb rubber replacement.

scholarly journals Durability of concrete pavement strengthened with asphalt layer with FRP fibres

2018 ◽  
Vol 64 (3) ◽  
pp. 81-97
Author(s):  
P. Tutka ◽  
R. Nagórski ◽  
P. Radziszewski ◽  
M. Sarnowski ◽  
M. Złotowska
Keyword(s):  
Fatigue Life ◽  
Concrete Slab ◽  
Asphalt Mixture ◽  
Concrete Pavement ◽  
Cement Concrete ◽  
Asphalt Overlay ◽  
Road Pavement ◽  
Traffic Loads ◽  
Pavement Structures ◽  
The Impact

SummaryPavements made of cement concrete, used for road constructions, are damaged during use. This applies to both the pavements of rural and forest roads with very low traffic loads, as well as road pavements with high traffic loads. One of the most effective ways of repairing damaged concrete cement pavements is through placing an asphalt overlay on a concrete slab. In order to increase the fatigue life of the asphalt overlay, asphalt mixtures are modified with fibres. One technological solution is to use FRP (Fiber Reinforced Polymer), an innovative material with improved properties. The aim of this paper is to assess the impact of asphalt overlays modified with a new type of fibres to strengthen the durability of weakened cement concrete pavement structures. On the basis of the conducted analyses, it was shown that the use of an asphalt layer reinforcement increases fatigue life, for both 15 cm thick prefabricated slabs and a typical road pavement for average traffic made of 25 cm doweled and anchored concrete slabs. There was a significant increase in the fatigue life of the concrete pavement structure as a result of modifying the overlaid asphalt mixture with FRP fibres.

scholarly journals 3D Physical Modelling Study of Shield-Strata Interaction under Roof Dynamic Loading Condition

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Shengli Yang ◽  
Hao Yue ◽  
Gaofeng Song ◽  
Junjie Wang ◽  
Yanyao Ma ◽  
...  
Keyword(s):  
Impact Loading ◽  
Loading Condition ◽  
Impact Load ◽  
Physical Modelling ◽  
Coal Face ◽  
Dynamic Impact ◽  
Immediate Roof ◽  
Cutting Height ◽  
The Impact ◽  
Dynamic Impact Loading

The dynamic hazards in the open face area caused by the impact load of the massive strong roof become increasingly severe with the increase in the cutting height of the longwall face and its depth of cover. Understanding the strata-shield interaction under the dynamic impact loading condition may relieve the dynamic hazards. In this paper, a 3D physical modelling platform is developed to study the interaction between the roof strata and the longwall shield under the dynamic impact load conditions. A steel plate is dropped to the coal face wall at a certain height above the immediate roof to simulate the free fall of the main roof and the dynamic impact loading environment. The occurrence of major roof falls is modelled at different height above the model and at different positions relative to the longwall faceline. The large-cutting-height and top-coal-caving mining methods are modelled in the study to include the nature of the immediate roof. The results show that the level of face and roof failures depends on the magnitude of the dynamic impact load. The position and height of the roof fall have an important influence to the stability of the roof and face. The pressures on the shield and the solid coal face are relieved for the top-coal-caving face as compared to the large-cutting-height face.

scholarly journals Influence of Cyclic Impact Loading and Axial Stress on Dynamic Mechanical Properties of Burst-Prone Coal

2021 ◽  
Vol 2021 ◽  
pp. 1-10 ◽  
Author(s):  
Shuang Gong ◽  
Zhen Wang ◽  
Lei Zhou ◽  
Wen Wang
Keyword(s):  
Mechanical Properties ◽  
Impact Loading ◽  
Coal Sample ◽  
Impact Load ◽  
Axial Stress ◽  
Dynamic Mechanical Properties ◽  
Dynamic Mechanical ◽  
Cyclic Impact Loading ◽  
Cyclic Impact ◽  
The Impact

High in-situ stress and frequent dynamic disturbances caused by the mining process in deep coal mines can easily induce dynamic disasters such as coal burst. We conducted laboratory experiments to assess the effects of the axial stress loading and dynamic cyclic impact loading on the dynamic mechanical properties of burst-prone coals by using a modified split Hopkinson pressure bar (SHPB). Comparisons were made using two types of burst-prone and burst-resistant coal samples. The mineral components, organic macerals, and dynamic mechanical features of both burst-prone and burst-resistant coal samples were comparatively analyzed based on the obtained X-ray diffraction (XRD), optical microscope observations, and dynamic compressive stress-strain curves, respectively. The results of the microstructure analysis indicated a larger difference between the minimum and maximum reflectances of vitrinite for burst-prone coal. Compared to the burst-resistant coal samples, the burst-prone coals contained less corpocollinite and fusinite. While applying a high axial static load combined with cyclic impact load, the coal samples showed the characteristics of fatigue damage. The results also demonstrated that preaxial stress affected the burst resistance of coal samples. The greater the preaxial stress was, the less the coal samples could withstand the dynamic cyclic impact load. In comparison to the burst-resistant coal sample, the burst-prone coal sample showed a larger dynamic compressive strength and a lower deformation. They were also more positively capable of the propagation and activation of the coal burst. We believe that the results of the study are conducive to further understanding of the distribution of microcomponents of burst-prone coals. The results are also beneficial for realizing the dynamic mechanical characteristics of burst-prone coals under the impact of cyclic dynamic load.

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