Properties and Application of Controlled Foundation Materials from Construction Waste and Pit Silt

Abstract:

In order to deal with the problem of backfilling in the narrow area of the underpass in the high-load flight area， a large amount of construction waste and silt produced by the reconstruction and expansion of Jinan Yaoqiang Airport was used as the main aggregate to prepare the controlled low-strength materials（CLSM） with the characteristics of high fluidity， self-compaction， and high strength. The test results show that the strength of the test group mixed with construction waste or stone debris increases significantly compared with the only silt used. The modification effect of construction waste is about 80% higher than that of stone debris. It is more economical to add construction waste than stone debris， but not for the increase of the cement content. The dry - wet cycle strength of the best mix ratio decreases and stabilizes at about 1 MPa， with the mass loss rate stabilizing at about 1%. The compression performance is the same as soil with a 6% cement quality score， and the compressive deformation after the dry - wet cycle is much less than that of silt， which meets the long-term bearing requirements of the foundation in flight area.

Key words:road engineering;foundation pit backfill;controlled low strength materials(CLSM);compressive strength;durability