Assessment of the Effect of Replacing Normal Aggregate by Porcelinite on the Behaviour of Layered Steel Fibrous Self-Compacting Reinforced Concrete Slabs under Uniform Load

Abstract

In this research, an attempt has been made to study the effect of replacing all normal-weight aggregate “NWA” by lightweight aggregate “LWA” (having a volume equal to 60% of the volume of normal-weight aggregate) on the behaviour of layered steel fibrous self-compacting reinforced concrete slabs with various volume fractions of steel fiber under uniform area load using fine sand technique. The experimental work consists of two groups “NWA” and “LWA,” each group consists of three slab specimens (having an aspect ratio equal to the golden ratio, i.e., 1.618), the thickness of each slab is divided into two equal layers, the top layer is free from steel fibers, while the steel fibers exist only in the bottom layer with three volume fractions (0%, 0.4%, and 0.8%). Ultimate uniform load of the slabs decreases with the increase in steel fiber content, while the percentage of decrease in the bulk density remains rather constant. It was also found that the ultimate uniform load of the slabs in each group is significantly improved with increasing steel fiber content, and the percentage of this improvement is higher in lightweight concrete “LWC” than in normal-weight concrete “NWC” Finally, it was noticed that when steel fiber increased, the flexural strength of slabs increased higher than shear strength; therefore, the mode of failure has been changed from bending to shear mode for slabs of both groups “NWC” and “LWC.”

The influence of chopped copper fibre (CF) on the improvement of pure gypsum by compressive strength

“…Regarding the use of strengthening substances, a good deal of research demonstrates the relevance of including various fibres in gypsum mixtures [3,[18][19][20][21][22][23]. This is because the fibres increase the gypsum tensile strength and shape stability to support the mixture to reduce degradation and breakdown.Many researchers have studied the effect of even more substances such as steel fibre or chipped carbon fibres to reinforce a concrete mix, cement mortar, and asphalt concrete admixtures [24][25][26][27][28][29][30][31][32].The current work proposes to design Pure Gypsum (PG) of unique fibres that strengthen as a composite form by use of compact and ductile copper fibres haphazardly scattered in the gypsum. Copper fibres present high ductility [33] to improve problematic brittle material fractures to become ductile fractures and also block the tendency to pull-out from the gypsum.…”