Strength Chatacteristics and Micro-Mechanism of Alkali-Activated Steel Slag-Blast Furnace Slag Road Base Composite Material

Abstract

Abstract: Focusing on the three issues of steel slag recycling, the strength enhancement of steel slag-blast furnace slag composite material as well as the microscopic action mechanism, the macroscopic strength of the mixture under different curing ages was analyzed from the two indicators of unconfined compressive strength and splitting strength. Besides, the internal mechanism of hydration products and strength formation of steel slag-blast furnace slag road base material under the lime activated were researched by XRD, SEM and thermogravimetric analysis. The strength test results show that when the mineral slag content is within 10% (mass fraction) and the mass ratio of lime and slag is between 1∶1 and 1∶2, the unconfined compressive strength and splitting strength of the mixed materials are higher than other lime and slag ratio at all ages. The microscopic test results reveal that an appropriate amount of Ca(OH)₂ can promote the hydration reaction rate of SiO₂ in the mineral slag, and improve the early strength of the composite material. In addition, the filling effect of the ettringite generated by the hydration reaction, fly ash and the inert components in the steel slag is also a favorable factor for the early strength growth of the material. The pozzolanic effect of fly ash and the continuous hydration reaction of C₂S in steel slag are contributed to the improvement of the later strength of the composite material.

Key words: road engineering, road base material, steel slag, blast furnace slag, hydration, strength chatacteristic

CLC Number:

TU521

WU Min, XIE Shenghua, GE Genwang. Strength Chatacteristics and Micro-Mechanism of Alkali-Activated Steel Slag-Blast Furnace Slag Road Base Composite Material[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2021, 40(8): 2640-2646.

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