Strength and Microstructure of Geopolymer Stabilized Recycled Asphalt Mixture

Abstract

Abstract: Developing new green road building materials with high early strength and low energy consumption is of great significance to highway construction and maintenance in China. The geopolymer stabilized cold recycled mixture (GCRM) was prepared by using geopolymer to stabilize 100% recycled asphalt mixture in this paper. The effects of slag content, water glass modulus, activator content and geopolymer content on the splitting strength of GCRM with different curing time and its time-varying law were studied. The microscopic morphology and structural composition of the mixture were analyzed by scanning electron microscopy and energy dispersive spectroscopy. The results show that the early strength of GCRM develops rapidly, which is significantly higher than that of cement emulsified asphalt stabilized cold recycled mixture. GCRM has the best early strength and its 7 d splitting strength can reach 1.7 MPa when the slag content is 30% (mass fraction), the water glass modulus is 1.0, the activator content is 50%(mass fraction) and the geopolymer content is 8% (mass fraction). Microstructure analysis shows that the cracks of GCRM failure interface appear in the position with low geopolymer reaction degree. Besides, the calcium aluminosilicate hydrate (C-A-S-H) layered gel structure is more conducive to the development of the mechanical strength for GCRM.

Key words: recycled asphalt mixture, geopolymer, cold recycled mixture, road engineering, strength development, microstructure

CLC Number:

U414

LIN Juntao, XIA Yu, LI Wei, XIE Chuankai. Strength and Microstructure of Geopolymer Stabilized Recycled Asphalt Mixture[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2023, 42(1): 364-372.

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