Static, dynamic mechanical properties and microstructure characteristics of ultra-high performance cementitious composites

摘要

A new type of construction material named ultra-high performance cementitious composite (UHPCC) was developed in order to reduce the production cost and energy consumption of reactive powder concrete (RPC). Six different mixture proportions of UHPCC were designed, and their properties, including workability (slump test), static mechanical properties (compressive strength and flexure strength), and dynamic mechanical properties (dynamic compressive strength, toughness and fracture pattern), were investigated. Finally, the microstructure of the UHPCC was studied. The experiment result indicate that the compressive and flexural strength of UHPCC can reach 150–200 MPa and 15–50 MPa under standard curing conditions, respectively, which is close to RPC200. Besides, the steel fiber has significant improvement on mechanical properties of UHPCC. The dynamic impact test results show that UHPCC has obvious strain rate effects. Besides, UHPCC exhibits excellent properties to resist dynamic impact. The microstructure investigation showed that UHPCC has dense microstructures and very strong bonds of the interfacial transition zone between cementitious paste and fine aggregate steel fiber.