Using alkali-activated slag ferrocement to strengthen corroded reinforced concrete columns

An experimental program was conducted to explore the use of alkali-activated slag ( AAS) ferrocement to strengthen corroded reinforced concrete columns. Direct tensile tests were conducted on AAS plate specimens with different layers of stainless steel wire meshes ( SSWM). Empirical equations for determining tensile strength of AAS ferrocement are provided with contribution from both AAS mortar and SSWM. Ten full-scale column specimens were prepared and seven of them suffered artificial accelerated corrosion at corrosion level of 8.9 %. Three corroded specimens were subsequently strengthened by AAS ferrocement with two layers of SSWM. The specimens were tested under axial, small and large eccentric compression, respectively. Experimental results have shown that the corroded columns suffer loading capacity losses from 21 to 30 % as compared with the control specimens. AAS ferrocement strengthening can enhance the loading capacity of corroded columns by 37-72 %. Confinement effect of AAS ferrocement is observed on specimens under axial and small eccentric compression. A model is proposed to predict the loading capacity of specimens strengthened by AAS ferrocement and reasonable predictions are obtained.