The effect of supplementary cementitious material systems on dynamic compressive properties of ultra-high performance concrete paste

Supplementary cementitious materials (SCMs) have been widely used to replace cement in UHPC, which benefits to reducing CO2 emissions and declining construction costs. However, the influence of SCMs on the dynamic compressive properties of Ultra-high performance concrete (UHPC) paste has not been well understood. Here, the workability, pore structure, quasi-static compressive strength and dynamic compressive properties of UHPC paste with different SCM systems are comprehensively studied. The results show that the substitution of cement by ground granulated blast furnace slag (GGBS) and limestone powder (LP) increases workability. With the substitution rate of 10% LP, the microstructure of M2 becomes denser. With the further increasing replacement of GGBS and LP, the porosity increases, while the quasi-static compressive strength and dynamic compressive properties trend to decrease, but the extent is limited. The compressive properties such as dynamic compressive strength, dynamic increase factor (DIF), peak strain and toughness are highly dependent on the strain rate. An applicable DIF model for UHPC is established at the strain rate of 53.9 - 170.7 s(-1). The fractal dimension increases with the rising of GGBS and LP. Additionally, a positive linear relationship is observed between the fractal dimension and the denary logarithms of the strain rate.

Automated summary

Supplementary cementitious materials (SCMs) can replace cement in UHPC, leading to reduced CO2 emissions and construction costs. This study comprehensively investigates the influence of different SCMs on the workability, pore structure, quasi-static compressive strength, and dynamic compressive properties of UHPC paste. The results show that using ground granulated blast furnace slag (GGBS) and limestone powder (LP) increases workability but also leads to increased porosity and decreased compressive properties at higher replacement rates.