Mechanical properties and bond strength degradation of GFRP and steel rebars at elevated temperatures

Mechanical properties of normal and high strength concretes subjected to high temperatures and using image analysis to detect bond deteriorations

Purpose




This paper aims to inspect the effect of indirect elevated temperature on the mechanical performance of nano silica concrete (NSC). The effect on both compressive and bond strengths is studied. Pre- and post-exposure to elevated temperature ranges of 200 to 600°C is examined. A range covered by three percentages of 1.5, 3 and 4.5 per cent nano silica (NS) in concrete mixes is tested.




Design/methodology/approach




Pre-exposure mechanical tests (normal conditions – room temperature), using 3 per cent NS in the concrete mix, led to the highest increase in both compressive and bond strengths (43 per cent and 38.5 per cent, respectively), compared to the control mix without NS (based on 28-day results). It is worth noticing that adding NS to the concrete mixes does not have a significant effect on improving early-age strength. Besides, permeability tests are performed on NSC with different NS ratios. NS improved the concrete permeability for all tested percentages of NS. The maximum reduction is accompanied by the maximum percentage used (4.5 per cent NS in the NSC mix), reducing permeability to half the value of the concrete mix without NS. As for post-exposure to elevated-temperature mechanical tests, NSC with 1.5 per cent NS exhibited the lowest loss in strength owing to indirect heat exposure of 600°C; the residual compressive and bond strengths are 73 per cent and 35 per cent, respectively.




Findings




The dispersion technique of NS has a key role in NSC-distinguished mechanical performance with NSC having lower NS percentages. NS significantly improved bond strength. NS has a remarkable effect on elevated temperature endurance. The bond strength of NSC exposed to elevated temperatures suffered faster deterioration than compressive strength of the exposed NSC.




Research limitations/implications




A special scale factor needs to be investigated for the NSC.




Originality/value




Although a lot of effort is placed in evaluating the benefits of using nano materials in structural concrete, this paper presents one of the first outcomes of the thermal effects on concrete mixes with NS as a partial cement replacement.

https://www.emerald.com/insight/content/doi/10.1108/JSFE-10-2017-0041/full/pdf

Assessment of mechanical strength of nano silica concrete (NSC) subjected to elevated temperatures

Reinforced concrete (RC) structural members generally exhibit a fairly good fire resistance due to their low thermal conductivity and high thermal capacity. However, under prolonged duration of exposure, RC members experience loss of strength and stiffness. An experimental investigation is carried out to examine the influencing factors affecting the structural performance of the RC beams of different strength grades exposed to standard fire. Specimens were heated as per standard fire curve. Different grades of RC beams (i.e. M20, M30, M40 and M50) are tested under two-point loading. The effect of standard fire on the load-deflection response, first crack load, ultimate load, temperature in rebar, yield strength of rebar and moment of resistance are investigated in the RC beams. Temperature in steel at specified locations of a RC beam is also measured to determine the extent of damage. It is observed from the investigation that the mode of failure is dependent on many material parameters (w/c ratio, density, porosity) and structural factors (compressive strength of concrete, yield strength of rebar). Damage level of concrete with lower grade was higher up to 120min duration of heating and after that loss in strength of concrete with higher grade is significant. Water-to-cement ratio, compressive strength, temperature level in concrete or steel and rebar area are some of the key factors affecting the loss in strength of RC beams at elevated temperature.

Investigation on structural and thermal performance of reinforced concrete beams exposed to standard fire

Finite element stress analysis of a reinforced high-strength concrete column in severe fires

Structural behavior of reinforced concrete structures at high temperatures

Popular Tasks used by Researchers

How can I help with your research?

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

We encountered an error while loading the panel. Please try refreshing the page.

Something went wrong

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

Anyone with the link can view this chat. You can switch it back to private anytime.

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Tetsuo Mochida

Author Tools

Chat about Author

Papers

Structural behavior of reinforced concrete structures at high temperatures