scholarly journals Condition Assessment and Structural Audit Before and After Repair of Fire Damaged Structure and Ansys Simulation of Column Jacketing

2019 ◽  
Vol 8 (2S3) ◽  
pp. 492-498
Keyword(s):  
Static Loading ◽  
Evaluation Process ◽  
Element Model ◽  
Ultrasonic Pulse Velocity ◽  
Condition Assessment ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Cell Potential ◽  
Ansys Simulation ◽  
Before And After

This study give details about the rehab process of fire damaged reinforced concrete buildings in basically three categories; condition evaluation, decision making, rehabilitation & retrofitting. Evaluation process of damaged building is based on understanding of condition survey and condition assessment of fire damaged structure. Condition survey includes detailed visual inspection of building whereas condition assessment includes non-destructive testing of building (such as Rebound Hammer test, Ultrasonic Pulse Velocity test, Carbonation test, pH test, Half Cell Potential test etc.). Based on survey and assessment, various repair and retrofitting schemes have been suggested. RC members often need strengthening to raise their capacity to sustain the applied load. This research investigates the behavior of RC columns strengthened using RC jacket technique. A finite element model was stimulated in ANSYS WORKBENCH to study the performance of these columns with and without jacketing, which has been designed for static loading. Based on ansys simulation and Comparison of test result before and after jacketing, it can be said that structure is safe in static loading condition

scholarly journals Tensile Strength and Dynamic Modulus of Pervious Polymer Concrete with Freezing and Thawing Cycles

2021 ◽  
Vol 21 (6) ◽  
pp. 209-215
Author(s):  
Yunje Lee ◽  
Jaehun Ahn ◽  
Yungtak Oh ◽  
Jaegeon Lee
Keyword(s):  
Tensile Strength ◽  
Dynamic Modulus ◽  
Low Impact Development ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Polymer Concrete ◽  
Freezing And Thawing ◽  
Test Standards ◽  
Before And After

The expansion of impervious areas owing to urbanization has adverse effects on water circulation. The application of low-impact development techniques to solve these problems is gaining popularity. Among others, Permeable pavements are the most widely employed low-impact development techniques. In this study, the dynamic modulus and tensile strength of pervious polymer concrete pavement were evaluated before and after freezing-thawing cycles. A tensile strength test, performed to check the soundness of the pervious polymer concrete, yielded a tensile strength and tensile strength ratio of 0.66 to 0.96 MPa, and 72 to 83%, respectively. The ultrasonic pulse velocity was measured to determine the dynamic modulus according to the freezing-thawing cycles. When 300 freezing-thawing cycles were performed, the dynamic modulus was analyzed to drop to a level of 77~85% of the initial value. The standards for freezing and thawing tests of pervious concrete have not yet been established. It is necessary to develop test standards for freezing-thawing resistance of pervious concretes considering climate change.

scholarly journals Effect of Stone Dust on the Mechanical and Microstructural Properties of Opc based Concrete Subjected to Acid Exposure

2019 ◽  
Vol 8 (3) ◽  
pp. 7488-7492 ◽  
Keyword(s):  
Concrete Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Acid Exposure ◽  
Fine Aggregate ◽  
Cell Potential ◽  
Stone Dust ◽  
Different Types ◽  
Mechanical And Microstructural Properties

A separate approach of sustainable development is to make the structures durable. More durable structures need to be replaced less frequently and will reduce the need for cement. Such increase in durability can be achieved by choosing appropriate mix designs and selecting suitable aggregates and admixtures. In this experiment sand (fine aggregate) is partially replaced by stone dust to make the concrete mix sustainable in nature. This study also investigates the durability of different types of concrete in acid exposure. Cube compressive strengths of different mixes have been compared to see how the concrete strength differs from original mixes. In addition different types of non-destructive tests such as ultrasonic pulse velocity test, rebound hammer test and half-cell potential tests have also been performed on the concrete samples for better analysis of their strength and durability characteristics. Specimens were analysed through the Scanning Electron Microscope to understand the microstructural changes of concrete samples. Energy dispersion X-ray analysis was also done to understand the changes in the nature of the hydration products of some specimen.

scholarly journals Verifying Moisture Damage Impact in Asphalt Concrete with the Aid of Nondestructive Test NDT

2020 ◽  
Vol 12 (1) ◽  
pp. 13-20
Author(s):  
Saad Issa Sarsam ◽  
Nazar Sajad Kadium
Keyword(s):  
Elastic Modulus ◽  
Asphalt Concrete ◽  
Ultrasonic Pulse Velocity ◽  
Moisture Damage ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Coefficient Of Determination ◽  
Before And After ◽  
Base Course ◽  
The Impact

One of the major concerns of pavement durability is its susceptibility to moisture damage. In this investigation, non-destructive test NDT has been implemented to detect the moisture damage issue. Asphalt concrete specimens were prepared using the traditional Marshall method for wearing, binder and asphalt stabilized base course. Specimens were traversed by ultrasound pulse velocity before and after practicing the moisture damage procedure. The variation of dynamic and elastic modulus before and after the moisture damage was considered and related to tensile strength ratio TSR. It was noted that the pulse velocity decline by (11, 11.2 and 16.4) % and the dynamic modulus declines by (28, 6.6 and 28.5) % for asphalt concrete wearing, binder and base courses respectively after moisture damage. The elastic modulus exhibits no significant variation after moisture damage for wearing course while it declines by (9 and 11.7) % for binder and base courses respectively after moisture damage. It was concluded that the elastic and dynamic moduli were unable to clearly distinguish the impact of moisture damage, whereas the Seismic modulus calculated from the Ultrasonic Pulse Velocity test was effective in distinguishing such impact. The linear equation obtained with good coefficient of determination can explain 74 % of the variation in the seismic modulus after moisture damage.

scholarly journals Ultrasonic assessment and finite element modelling of thermo-mechanical damage in mortar

2017 ◽  
Vol 10 (4) ◽  
pp. 826-837 ◽  
Author(s):  
C. L. Nogueira
Keyword(s):  
Finite Element ◽  
Mechanical Loading ◽  
Peak Load ◽  
Mechanical Damage ◽  
Element Model ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Transverse Waves ◽  
Ultrasonic Assessment

ABSTRACT Experiments were conducted to evaluate degradation of mechanical properties in mortar specimens subjected to thermal and mechanical loading. Ultrasonic pulse velocity was used to assess changes in the microstructure of the specimens due to thermal and mechanical loads applied separately. Both longitudinal and transverse waves were used. At first the specimens were tested in the undamaged stage, and then they were also tested after their exposure to a non-uniform thermal load only, finally, mechanical loading was applied until peak load. A finite element model was used in the dynamic simulation of pulses propagation. Results showed that mortar mix with a larger proportion of coarser aggregates is more sensitive to mechanical loading after exposure to heat than mortar with lesser and smaller aggregate contents. Mortar mix design with less and finer aggregate did not show a reduction in the pulse velocity as intense as the mortar with more coarse aggregate, which indicates a less severe diffuse microcracking.

scholarly journals MECHANICAL, THERMAL AND DURABLE PERFORMANCE OF WASTES SAWDUST AS COARSE AGGREGATE REPLACEMENT IN CONVENTIONAL CONCRETE

2018 ◽  
Vol 81 (1) ◽  
Author(s):  
Gassan Fahim Huseien ◽  
Ruhal Pervez Memon ◽  
Ziyad Kubba ◽  
Abdul Rahaman Mohd Sam ◽  
Mohammad Ali Asaad ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Elevated Temperatures ◽  
Evaluation Process ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Conventional Concrete ◽  
Long Duration ◽  
Mechanical And Physical Properties

Wood yields a number of by-products and Sawdust is as useful as others. Sawdust is regarded as a waste material and is effectively utilised as sawdust concrete in the construction of buildings. It is capable to be utilised as light-weight concrete and holds the quality of long duration heat transfer. In this study, three different ratios (1:1, 1:2 and 1:3) volume mix proportions of cement to sawdust were adopted to make sawdust concrete. At varied intervals of 7, 28 and 56 days of air curing, thermal and mechanical properties like workability, density, elastic modulus, strength and heat transfer were probed of mentioned sawdust concrete proportions. The resistance to elevated temperatures was also evaluated after 28 days of age; weight loss, residual compressive strength, surface texture and ultrasonic pulse velocity were considered in evaluation process. The findings showed that increase in sawdust volume affected to decrease the workability, strength and elevated temperatures resistance. However, the concrete having higher proportion of sawdust performed competently and well in terms of thermal conductivity. Moreover, a decrease in the heat transfer of sawdust was also observed. Examining the all-embracing mechanical and physical properties, sawdust can be effectively utilised in the construction of buildings.

scholarly journals Suitability of Nondestructive Testing of Asphalt Concrete for Detecting the Impact of Moisture Damage

2021 ◽  
Vol 3 (1) ◽  
pp. 73-83
Author(s):  
Saad Issa Sarsam
Keyword(s):  
Nondestructive Testing ◽  
Asphalt Concrete ◽  
Ultrasonic Pulse Velocity ◽  
Moisture Damage ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Concrete Mixture ◽  
Before And After ◽  
Base Course ◽  
The Impact

Asphalt pavement susceptibility to moisture damage is considered as a major issue in the durability and service life of the roadway. Quick and nondestructive testing of asphalt concrete pavement are the major concern for predicting its suitability for evaluation. In the present investigation, nondestructive test has been implemented to detect the moisture damage issue of asphalt concrete mixture. Asphalt concrete specimens were prepared using Marshall method. Aggregates gradation of wearing, binder and base course was implemented for the preparation of the specimens. Specimens were tested for ultrasonic pulse velocity before and after practicing the moisture damage procedure. The variations of seismic modulus among various gradation before and after the moisture damage were considered as a criterion for moisture damage and related to tensile strength ratio TSR. It was observed that the pulse velocity decline by a range of (11 to 16) for asphalt concrete after moisture damage. It was concluded that the Seismic modulus as calculated from the ultrasonic pulse velocity test was effective in distinguishing the impact of moisture damage. The seismic modulus at optimum asphalt content decline by (34.7, 46.7, and 52.6) % after moisture damage for wearing, binder, and base course mixtures respectively. The ultrasonic pulse velocity test is recommended for assessing the susceptibility of asphalt concrete mixture to moisture damage.

scholarly journals Implication of Nondestructive Test NDT for Evaluation of Crack Healing in Asphalt Concret

2020 ◽  
Vol 2 (1) ◽  
pp. 1-5
Author(s):  
Saad Issa Sarsam
Keyword(s):  
Asphalt Concrete ◽  
Healing Process ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Load Test ◽  
Loading Frequency ◽  
Crack Healing ◽  
Micro Cracks ◽  
Before And After

Asphalt concrete practices heavy loading and environmental impacts through the service life of the pavement. Micro cracks usually initiate and accumulate to form various types of distresses. However, asphalt concrete has the ability of self-healing under rest period and environment conditioning. Asphalt concrete is a composite material consisting of aggregates, bitumen, and air voids. Its mechanical behavior is complex due to its dependency of temperature, loading frequency, and strain level. In this investigation, asphalt concrete specimens of wearing course have been prepared in the laboratory and subjected to repeated indirect tensile stresses to initiate the micro-cracks. The test was stopped after 1200 load repetitions, and the specimens were stored in an oven at 60°C for 120 minutes to allow the crack healing process by external heating to start. Specimens were returned to the testing chamber and were subjected to another round of load repetitions. Specimens were tested before and after load repetitions and crack healing with the aid of ultrasonic pulse velocity traversing the specimen using pundit instrument. The healing indicator was the change in pulse velocity before and after the repeated load test and before and after healing process. It was concluded that the velocity decreases as the loading cycles proceeds indicating the start of damage, while the ultrasonic pulse velocity increases after the micro-crack healing process.

scholarly journals Preliminary High-Temperature Tests of Textile Reinforced Concrete (TRC)

Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 522
Author(s):  
Panagiotis Kapsalis ◽  
Tine Tysmans ◽  
Svetlana Verbruggen ◽  
Thanasis Triantafillou
Keyword(s):  
Reinforced Concrete ◽  
Residual Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Textile Reinforced Concrete ◽  
Simple Set ◽  
Before And After ◽  
Set Up ◽  
Flexural Tests

Fire-testing of Textile Reinforced Concrete (TRC) is an interesting field in which quite limited research has been conducted so far. In this paper some preliminary tests are presented, where mortars used as binders are heated to 850 °C and their residual strength is tested, while the Ultrasonic Pulse Velocity (UPV) is also measured, before and after heating, and compared. Additionally, TRC specimens are subjected to flame exposure with a simple set-up and the residual strength is also tested by flexural tests. It is concluded that even with simple set-ups, interesting results can be obtained regarding the structural degradation of the material.

PENGKAJIAN KEKUATAN BETON STRUKTUR JEMBATAN PASCA KEBAKARAN

2013 ◽  
Vol 12 (3) ◽  
Author(s):  
Sudarmadi Sudarmadi
Keyword(s):  
Compressive Strength ◽  
Concrete Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Test Results ◽  
Concrete Compressive Strength ◽  
Strength Assessment ◽  
Concrete Testing

In this paper a case study about concrete strength assessment of bridge structure experiencing fire is discussed. Assessment methods include activities of visual inspection, concrete testing by Hammer Test, Ultrasonic Pulse Velocity Test, and Core Test. Then, test results are compared with the requirement of RSNI T-12-2004. Test results show that surface concrete at the location of fire deteriorates so that its quality is decreased into the category of Very Poor with ultrasonic pulse velocity ranges between 1,14 – 1,74 km/s. From test results also it can be known that concrete compressive strength of inner part of bridge pier ranges about 267 – 274 kg/cm2 and concrete compressive strength of beam and plate experiencing fire directly is about 173 kg/cm2 and 159 kg/cm2. It can be concluded that surface concrete strength at the location of fire does not meet the requirement of RSNI T-12-2004. So, repair on surface concrete of pier, beam, and plate at the location of fire is required.

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