Strengthening of heat damaged reinforced concrete cylinders

The purpose of this study is to investigate the effectiveness of various strengthening techniques in restoring heat damaged reinforced concrete. A series of 40 reinforced concrete cylinders were tested under concentric compression after being jacketed externally with high strength fiber reinforced concrete (HSFRC), Ferrocement (FC) and Glass fiber reinforced polymer (GFRP) jackets. Concrete specimens were exposed to elevated temperatures ranging from room temperature to 900 ºC. The overall response of strengthened specimens was investigated vis-à-vis un-strengthened specimens in terms of axial compression, axial displacement and axial stress strain behaviour. The results indicate that important gains in strength and ductility can be achieved by strengthening heat – damaged R.C cylinders by HSFRC, FC and GFRP external Jacketing. GFRP jacketing was found to be the most effective method of strengthening fire or heat damaged concrete structures

Anchorage Capacity of Headed Bars in Steel Fiber Reinforced Concrete

Headed bars (HB) with different head shapes (Square, Circular, and Rectangular) and bar diameters (db: 16, 20, and 25 mm) embedded in steel fiber reinforced concrete have been subjected to pull-out test. The influence of head shapes, concrete compressive strength (M20 and M40), db, and steel fibers (0, 0.5, 1, and 1.5%) on the anchorage capacity of HB have been evaluated. Numerical model for improving the anchorage capacity of HB has also been proposed. Results have revealed that the anchorage capacity of HB increases with the increase in concrete compressive strength, db, and steel fibers, which have been validated by non-linear regression analysis using dummy variables. Two failure modes namely, steel and concrete-blowout have been observed and the prevailing mode of failure is steel failure. Based on load-deflection curves and derived descriptive equations, it is observed that the circular HB has displayed the highest peak load.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Spalling behaviour of nano SiO

The behaviour of high strength concrete exposed to high temperature and incorporating Nano SiO2 and Micro SiO2 is presented. An experimental programme was developed and carried out which involved testing of Nano SiO2 and Micro SiO2 incorporated high strength concrete specimens exposed to temperatures ranging from room temperature to 800 °C. Maximum spalling was noted in Micro + Nano silica specimens. However, the maximum strength loss and temperature induced cracking was noticed in Nano silica specimens

Spalling behaviour of nano SiO2 high strength concrete at elevated temperatures

The behaviour of high strength concrete exposed to high temperature and incorporating Nano SiO2 and Micro SiO2 is presented. An experimental programme was developed and carried out which involved testing of Nano SiO2 and Micro SiO2 incorporated high strength concrete specimens exposed to temperatures ranging from room temperature to 800 °C. Maximum spalling was noted in Micro + Nano silica specimens. However, the maximum strength loss and temperature induced cracking was noticed in Nano silica specimens