Performance evolution and tensile behaviour of long-term exposed UHPC under sustained load, aggressive environments and autogenous healing

An extended experimental campaign was conducted to analyse the evolution of UHPC tensile performance over time as affected by sustained flexural load and aggressive environments both interacting with its autogenous self-healing capacity. A new methodology including destructive non-destructive tests proposed. Three different mix designs were tested, steel fibres, crystalline admixture, various nanomaterials. Specifically, first batch included alumina nano-fibres, while second one cellulose nanocrystals. The last used a reference did not include Thin beam specimens (500x100x30 mm) pre-cracked exposed three environments, under four-point bending load. cured for 1, 2, 3, 6, 9, 12 months respectively, being chloride solution, geothermal water, tap water reference. After aforesaid scheduled exposure times, two nominally identical tested each condition, in direct tension. To compare results, simplified five-point inverse analysis adapted beams slenderness, providing quadrilinear constitutive law derived from structural behaviour tests. Test results allowed highlight effects parameter – type material on effectiveness response, also defining their time. process resulted an almost complete recovery after or months, materials able maintain constant longer periods, regardless conditions they to.