EFFECTS OF CRYSTALLINE ADMIXTURES ON THE REPEATABILITY OF SELF HEALING IN FIBER REINFORCED CONCRETE

This paper analyzes the repeatability of autogenous and engineered self-healing in fiber reinforced concrete (FRC) with and without crystalline admixtures. To this purpose, the tensile response of two different mixes, differing by the presence of the crystalline admixture, was investigated, after a series of pre-cracking and conditioning cycles. An indirect testing methodology was employed to the aforementioned purpose, i.e. Double Edge Wedge Splitting (DEWS) test. Specimens were healed under three different exposure conditions: open air exposure, water immersion and wet/dry cycles. Specimens were pre-cracked up to a crack width of 0.25mm (pre-crack cycle) and then healed for one month, three or six months, tested again up to a crack width of 0.25mm (cycle after 1st healing) and re-healed for one or two further months. Comparison with specimens pre-cracked up to 0.25 mm and continuously healed for three months was also performed to assess the interaction between the presence of the crystalline admixture and the cracking/healing cycles. Investigation is still on-going, repeating healing/cracking cycles according to the scheme above