Compressive-Tensile Mechanics and Energy Consumptions of a Cementitious Composite with High Utilization of Steel Slag

In response to the National Development and Reform Commission’s “Guiding Opinions on Comprehensive Utilization of Large Solid Wastes during the Fourteenth Five Year Plan”, further expand the use of steel slag as concrete admixture in construction projects and other fields, and gradually improve the comprehensive utilization ratio, a cementitious composite with high utilization of steel slag (CHS) was developed, which is with the cement replaced by high-content super-fine steel slag powder (SSP) (replacement ratio υ ≥ 30%) as the cementitious materials, steel slag sand (SS) as the only aggregate and environmentally basalt fiber (BF) for toughening. It improves the utilization percentage of steel slag (SSP and SS) and reduces the consumption of natural resources such as cement and natural sand. Use BF to achieve better strength and toughness. In order to better understand the performance of CHS and make it better used in the engineering field. Study the influence of each component on the strength and energy consumption of compression and splitting tension, and strive to find the optimal proportion and lay the theoretical foundation for its application. Through the tests, the effects of high replacement ratio υ (30%–50%), low binder-aggregate ratio γ (0.31–0.44), and BF content ρ v (0%–2%) on the aspects of peak strength, force-deformation curve and energy consumption were analyzed. The results show that the standard curing f ck and f t,s can reach 40 MPa and 5 MPa respectively. With the increase of υ , the maximum axial compressive strength f ck and splitting tensile strength f t,s decreased insignificantly. The γ has an important influence on f ck and f t,s . When it increases from 0.31 to 0.44, f ck increases linearly by 63.1% to 40.4 MPa, while f t,s increases by 52.8% to 5.18 MPa. As ρ v increases, f ck and f t,s show a trend of first increasing and then decreasing. ρ v exerts a significant impact on the descending segments of stress-strain response curves of the compression which expressed as bilinear and trilinear models with different ρ v after normalization. The energy consumptions of peak, total, and residual ( E peak , E disp , E res ) show a slight downward trend with the increase of υ , a significantly upward trend with the increase of γ . With the increase of γ v , and E disp increase first and then tend to be flat, while E res always increases and the percentages of E res / E disp in the compressive test increase from 22.6% to 38.5%, reflecting