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 ۱-layer to ۳-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 C۱۵۷/C ۱۵۷M specification on three prism-shaped ‘۷۵mmx۷۵mmx۲۸۵mm’ specimens. NORAITE PA-۱ foaming agent was used to produce the desired density of LFC. All of ۳۲۴ specimens were tested for mechanical properties of LFC. The cast specimens were put to test at ۷days, ۲۸days and ۵۶ days. In compression strength test, cube dimensions of ۱۰۰mm side following BS EN ۱۲۳۹۰-۳:۲۰۰۹ were adopted. The flexural strength was conducted on  ‘۱۰۰mmx۱۰۰mmx۵۰۰mm’ beam specimens following BS ISO ۱۹۲۰-۸:۲۰۰۹. The specimens ‘۱۰۰mm in diameter and ۲۰۰mm in height’ were tested for split tensile strength considering ASTM C۴۹۶/ C۴۹۶M-۰۴e۱ specifications. The result showed that confinement with ۱۶۰g/m۲ (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 ۳-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 ۱۶۰۰kg/m۳ density confined/reinforced with ۳-layers of  FGM conquers the good performance in drying shrinkage and strength properties while the poor performance was shown by the unconfined LFC at ۶۰۰kg/m۳ density.

کلیدواژه ها:

drying shrinkage ، Durability ، Foamed concrete ، Strain ، Textile Fabric