Compaction method development and materials performance evaluation of large size cement-treated macadam materials

Abstract

Existing research mainly focuses on cement-treated macadam materials with a maximum nominal particle size (MNPS) of ≤ 37.5 mm, and there is little research on large size cement-treated macadam (LSCM) with an MNPS of ≥ 53 mm. In this paper, a self-developed vertical vibration testing equipment (VVTE) was used to compact an LSCM with an MNPS of 53 mm (hereafter, LSCM-50). Then, an appropriate specimen size for compacting LSCM-50 was determined. Moreover, a self-developed vertical vibration compaction method (VVCM) for laboratory-based compaction of LSCM-50 was proposed and its reliability was verified. Subsequently, the indoor mechanical properties and durability of the VVCM-fabricated LSCM-50 were studied. The results show that when the working frequency of VVTE = 32 Hz, upper system weight of VVTE = 122 kg, lower system weight of VVTE = 180 kg, nominal amplitude of VVTE = 1.2 mm, and static eccentric moment of VVTE = 0.215 kg·m, the compaction effect of LSCM-50 is the best. The correlation between the laboratory-VVCM-fabricated LSCM-50 samples and the on-site-drilled LSCM-50 cores is more than 90%. The mechanical properties of the LSCM-50 samples increase nearly linearly with the increase in the cement content but increase nonlinearly with the increase in the curing period. Additionally, the strength deterioration coefficient of the LSCM-50 samples does not decrease when the freeze–thaw cycles exceed seven, and the mass loss percentage of the LSCM-50 samples does not increase after being soured for 25 min. This paper provides a new method for compacting the LSCM and an evaluation of its mechanical properties and durability.