Stability Of Weathered Sand On The Highway

Weathered sand has benefits of wide spread, plenty of source and low cost. However it has drawbacks of low strength and unstable gradation. According to plenty of tests indoors and outdoors all kinds of pavement performances of weathered sand, cement stabilized weathered sand and lime-fly ash stabilized weathered sand are studied in the paper; the causes of low strength of weathered sand are analyzed and the methods to improve the strength of weathered sand are proposed.Firstly the paper systematically studies the mineral composition, gradation and its strength. Secondly the strength, rigidity, stability and anti-crack performance of cement stabilized weathered sand and lime-fly ash stabilized weathered sand are systematically studied. The effects indicate the cement stabilized weathered sand has high strength and rigidity, good performances of stability and anti-crack; the lime-fly ash stabilized weathered sand has high strength and good rigidity; however its stability and anti-crack performance are weaker. On the basis the methods of improving the pavement performances of weathered sand are studied. Precompression can improve the pavement performances of cement stabilized sand such as compression strength, splitting strength and anti-freezing performances and cement stabilized aggregates-weathered sand has high strength, good stability and economical efficiency. Finally the results of cement stabilized weathered sand as the subbase of express highway are verified through the tests outdoors.