Influence of Bi-directional Fibreglass Grid Reinforcement on Drying Shrinkage and Mechanical Properties of Lightweight Foamed Concrete

This experimental work is about the study of drying shrinkage followed by strength testing of lightweight foamed concrete (LFC) specimens with the confinement of woven fiberglass mesh (FGM) at three different densities. The LFC specimens were wrapped with 1-layer to 3-layer(s) of FGM for cube and cylinder specimens and in beam specimen, it was centrally spread along the longitudinal axis. The specimens were cured under air storage conditions and the drying shrinkage test was carried following ASTM C157/C 157M specification on three prism-shaped ‘75mmx75mmx285mm’ specimens. NORAITE PA-1 foaming agent was used to produce the desired density of LFC. All of 324 specimens were tested for mechanical properties of LFC. The cast specimens were put to test at 7days, 28days and 56 days. In compression strength test, cube dimensions of 100mm side following BS EN 12390-3:2009 were adopted. The flexural strength was conducted on ‘100mmx100mmx500mm’ beam specimens following BS ISO 1920-8:2009. The specimens ‘100mm in diameter and 200mm in height’ were tested for split tensile strength considering ASTM C496/ C496M-04e1 specifications. The result showed that confinement with 160g/m2 (GSM) of FGM significantly restricts the drying shrinkage of LFC specimens compared to control specimens and it decreases with the increases in layer(s) from l-layer to 3-layer(s) and density of LFC. The testing of the mechanical properties of LFC showed a direct proportionality between strength and LFC density and confinement layer(s). The failure pattern observed in all specimens was either by debonding or splitting of fibers of FGM. Thus, LFC at 1600kg/m3 density confined/reinforced with 3-layers of FGM conquers the good performance in drying shrinkage and strength properties while the poor performance was shown by the unconfined LFC at 600kg/m3 density.