The Preparation of Ground Blast Furnace Slag-Steel Slag Pavement Concrete Using Different Activators and Its Performance Investigation

Steel slag and ground blast furnace slag show good wear resistance, which is suitable for improving the abrasion performance of pavement concrete. This work presents an investigation of the activation of Na2SO4, Na2CO3 and Na2SiO3 on the GBFS-SS composite pavement concrete. The results showed that both Na2SO4 and Na2SiO3 can promote the strength development of the GBFS-SS composite cementitious system. Na2CO3 shows limited improvement in the strength of GBFS-SS composite paste. The GBFS-SS composite paste activated with Na2SiO3 and Na2SO4 combination shows hydration products of ettringite, portlandite and amorphous C-A-S-H gel. SO42− can accelerate the depolymerization of the aluminosilicate network in GBFS and SS vitreous structure, while SiO32− can only facilitate the pozzolanic reaction of GBFS and SS, but also participate in the hydration to form more C-A-S-H gel. Na2SO4 as the activator can reduce the dry shrinkage of the pavement concrete, while Na2SiO3 as the activator can further improve the compressive strength and abrasion resistance of the pavement concrete. The combined activation of Na2SiO3 and Na2SO4 shows a better effect on improving the performance of pavement concrete than the single Na2SiO3 or Na2SO4 activator. At the optimal content of 3% of Na2SiO3 and 1% of Na2SO4, the pavement concrete obtains the 60 d compressive strength of 73.5 MPa, the 60 d drying shrinkage of 270 × 10−6, the 60 d interconnected porosity of 6.85%, and the 28 d abrasion resistance of 28.32 h/(kg/m²).

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