Optimization of Cement Admixture and Performance Enhancement of Loess Roadbase

Abstract

Based on the practical difficulties in filling the roadbed of a highway in loess area, cement-reinforced loess was used as the roadbed filling material according to the geological conditions and filler distribution of the project. The mechanism of cement-reinforced loess was analyzed, and the linear fitting relationship between compaction of reinforced soil and CBR of bearing ratio was investigated by indoor tests with different cement dosage. Combined with the specification requirements for roadbed bearing ratio and modulus of resilience, the cement dosing of cement-reinforced loess for the project was determined. The study shows that: (1) cement as an admixture for loess roadbed improvement can significantly improve the mechanical properties of loess, and the dosage and the size of performance are linearly related. (2) The CBR and E₀ meet the specification requirements when the cement doping is 5% and 96% of the minimum compaction required for the upper roadbed is met; (3) The CBR value meets the specification requirements when the cement doping is 3% and 96% of the minimum compaction required for the upper embankment is met; (4) A cement doping of 4% is recommended, which achieves a good transition between the upper roadbed and the embankment, and meets the specification requirements for the lower roadbed;(5)The results of the study can provide a reference for the design and construction of cement-reinforced loess roadbeds.