Research on Performance of Pavement Cement Concrete Mixed with Iron Tailings and Fibers

Abstract

Abstract:In order to recycle iron tailings and fibers and analyze the performance of pavement cement concrete mixed with it, tests and numerical simulations are carried out. The compressive strength of concrete is significantly influenced by the content of Anshan iron tailings, and the highest 28-day compressive strength is 49.60 MPa with 25% iron tailings in sand. The flexural strength of concrete with iron tailings meets the specifications for pavement with 25-30% iron tailings in sand. Iron tailings with a particle diameter in the range of 0.15-0.3 mm are more advantageous. In general, basalt fiber play a greater role than polypropylene fiber in the flexural strength of concrete in this paper.Numerical simulations accurately reflect the performance trends of the tests.

Mechanical Properties and Hydration Mechanism of Iron Tailings–Cement-Based Supplementary Cementitious Materials

“…Figure 14 shows Ca 2+ , Si 4+ , and Al 3+ in different systems. From the figure, it can be seen that Ca 2+ , Si 4+ , and Al 3+ were present in the SS system when the system underwent the dissolution of C 3 S and C 2 S with the generation of C-(A)-S-H gel, which is reflected in Equations ( 5) and (6). The concentration of Ca 2+ , Si 4+ , and Al 3+ in the FA system behaved differently from that of SS, in which the concentration of Ca 2+ was lower and the concentration of Si 4+ and Al 3+ was higher, mainly due to the higher content of Al 2 O 3 in the FA, in which the reactive Al 2 O 3 was dissolved in the water and reacted with the water to form C-(A)-S-H gel, which is specifically reflected in Equation (7).…”

“…Data show that China's existing IOT stockpile has exceeded 5 billion tonnes, and the annual emissions of new IOTs are nearly 300 million tonnes, but the comprehensive utilisation rate of IOTs is only 27.69% [5]. Therefore, in recent years, the recycling of IOTs has gradually received attention, and more and more treatment methods have been proposed [6,7]. As some of the physicochemical properties of IOTs themselves are very comparable to those of current cement-based building materials, the utilisation of IOTs for construction materials is already one of the common ways of utilizing IOT resources, which mainly includes the production of cement and concrete, road construction materials, and building bricks, as well as high-value construction products such as microcrystalline glass, foam ceramics.…”