Assessment and restoration of bond strength of heat-damaged reinforced concrete elements

Shamseldein, Ayman; Elshafie, Hany; Rashad, Ahmed; Kohail, Mohamed

doi:10.1016/j.conbuildmat.2018.03.008

Cited by 44 publications

(11 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Also, the effect of using superplasticizers with different chemical bases is thoroughly investigated and naphthalin based admixtures seemed to have remarkable merits with Nano additives (Serag, Mohamed et al, 2014;Raouf et al, 2014). Enhancement in concrete mechanical behavior, as compressive strength, bond, durability, permeability, beside corrosion and elevated temperature resistance by using small ratios of Nano Silica (1.5 per cent to 3 per cent) in concrete mixes was not only reported by one of the authors (Ahmed et al, 2018;Serag et al, 2017;El-Feky et al, 2016), but similar results are reported by , Mohamed et al (2016); , ; Sherif (2019), Irshidat and Al-Saleh (2017); Mohammed et al (2014), Morsy et al (2010); Birgisson et al (2012); Ergün et al (2016); Ghazy et al (2015), Shamseldein et al (2018); Ghazaly et al (2018).…”

Section: Introductionsupporting

confidence: 66%

Assessment of mechanical and fire resistance for hybrid nano-clay and steel fibres concrete at different curing ages

Shalby

Elkady

Nasr

et al. 2019

JSFE

View full text Add to dashboard Cite

Purpose Nano-Clay (NC) is reported as a candidate partial replacement for cement, due to its abundance and relatively low cost - beside reported promotion of different concrete properties. On the other hand, Steel Fibres (SF) has proven to have a positive effect on post fire exposure residual strength of concrete. This paper aims to present the outcomes of a comprehensive research program assessing a hybrid mix between NC and SF in concrete mixtures (NCSF-CRETE). Design/methodology/approach Physical chemical and physical characterization of NC is performed using different tools as XRF spectrometer, and TEM micrograph. Fresh concrete properties of NSCF-CRETE as slump and air content are investigated. Enhancement in permeability using NSCF is verified by comparing its resistance to the penetration of chlorides resistance with regular concrete mix. Besides, the proposed NCSF-CRETE compressive strength is evaluated compared to mixes with NC and SF each used separately at different curing ages. Besides, NSCF and compared mixes are exposed to an indirect fire testing program – two hours exposure – for: 300, 450 and 600°C. Degradation in compressive strength was investigated after exposure to different temperatures and percentage of residual strength is reported. Findings Results indicated an improved performance of NCSF -CRETE of about 40% compared to regular concrete in compressive strength at normal conditions. This improvement extended to its behavior when subjected to indirect fire exposure NSCF also maintained 40% more strength than the residual in regular concrete mix – which suffered severe damage – after 2 h exposure to 600°C. Originality/value Using NCSF-Crete allows retrofitting the structure after exposure to such drastic conditions.

show abstract

Section: Introductionsupporting

confidence: 66%

Assessment of mechanical and fire resistance for hybrid nano-clay and steel fibres concrete at different curing ages

Shalby

Elkady

Nasr

et al. 2019

JSFE

View full text Add to dashboard Cite

show abstract

“…Zhai et al [50] showed that chemical and physical changes take place in both the cement paste and the aggregates and that the changes are different at different levels of temperature [51,52]. The deterioration of the concrete slabs is a very important phenomenon to be monitored because it requires cortical restoration interventions to reconstruct the damaged parts, eliminate cracks and protect the underlying structures from the penetration of substances capable of corroding the reinforcing rods [53,54].…”

Section: Mechanical Characterization Of the Samplesmentioning

confidence: 99%

Case study on the mineralogical and petrophysical analysis of reinforced concrete slabs of a highway viaduct of the S.G.C. Orte-Ravenna

et al. 2021

View full text Add to dashboard Cite

For the maintenance of the safety and security of people traveling on the road, renovation of the reinforced concrete is necessary, especially for bridge or viaduct slabs. Being able to quantify the degradation of slabs and propose methodologies for its retrofit or maintenance is crucial not only in the mineralogical-engineering field but also for socio-economic implications. In this study, samples of deck slabs of a viaduct from the highway E45 near the locality of Bagno di Romagna (Emilia Romagna, north of Italy) were subjected to a testing program to evaluate mechanical and mineralogical parameters through thermographic analyses, compression, and Ultrasonic Pulse Velocity tests and morphological observation. The analyses allow to better recognize the damage of the reinforced concrete samples and they have shown that the cause of the detachment of the asphalt has mainly a natural origin, due to temperature variations and precipitation, with a secondary cause in the anthropogenic impact. The work aims to understand the relationships between the structure of the aggregates and the characteristics of concrete to understand the development of degradation. This knowledge could be used to prevent future damages to the highways. Article Highlights• Concrete slabs analysed provided information about the relation between damage level, mechanical behaviour, size and distribution of aggregates.• Thermographic analyses were useful to understand how deep the damage was in the slabs and to detect any detachment of the asphalt. • Compressive tests, through the failure load value, shown that the ultimate strength level decreased due to formation of microcracks.

show abstract

“…More recently, Shamseldein et el. [11] performed experimental investigations on residual bond strength after exposure to elevated temperature using beam-end specimens. Compared to the standard pull-out specimen, the chosen specimen geometry (beam-end specimen) and test setup (unconfined) are more representative of the real conditions in a beam.…”

Section: Literature Reviewmentioning

confidence: 99%

Numerical investigations on post-fire bond behaviour of reinforcement in concrete

2019

View full text Add to dashboard Cite

Reinforced concrete (RC) structures may be subjected to accidental fire loads during their service life. In such a case, it is essential to have appropriate methods for the estimation of post-fire performance. One of the vital aspects for the performance of RC structures is adequate steel-to-concrete bond. The bond behaviour under ambient conditions is very well established. However, an appropriate model for the assessment of the post-fire bond capacity is still lacking. In order to provide more insight into the bond performance after fire, a 3D FE numerical study using a thermo-mechanical model with temperature dependent microplane model for concrete is performed. The effects of concrete cover, confinement through stirrups, fire duration and exposure type on post-fire bond performance are investigated using beam-end specimen. The results show a strong degradation of post-fire bond capacity, which is primarily attributed to the irreversible damage of concrete cover resulting from heating and cooling.

show abstract

Assessment and restoration of bond strength of heat-damaged reinforced concrete elements

Cited by 44 publications

References 32 publications

Assessment of mechanical and fire resistance for hybrid nano-clay and steel fibres concrete at different curing ages

Assessment of mechanical and fire resistance for hybrid nano-clay and steel fibres concrete at different curing ages

Case study on the mineralogical and petrophysical analysis of reinforced concrete slabs of a highway viaduct of the S.G.C. Orte-Ravenna

Numerical investigations on post-fire bond behaviour of reinforcement in concrete

Contact Info

Product

Resources

About