Study on Influence Factors of Compressive Strength of Low Density Backfill Foamed Concrete Used in Natural Gas Pipeline Tunnel

Foamed concrete is mostly used for backfilling of long-distance tunnels and compressive strength an important technical index to control the quality foamed concrete. The influence factors on low-density were obtained by single factor test method based targeted dry density strength. results show that HT composed pollution-free animal protein oil vegetable efficient foaming agent can produce stable foams. cementation ability cement be fully expressed when a water ratio 0.45~0.5 employed, making have higher than 2 MPa. foam content inversely proportional concrete, volume slurry should 2:1~3:1. fly ash also but positively density. When admixture 40~55%, with low not less mixing proportion changed in reasonable range meet requirements different projects.