Foamed Cement Banking And Applications In Highway Construction

As a kind of geotechnical material, light material is made of artificial materials, the primary character of which is that it is lighter than common soil while the intensity and the deformation feature may be equal to or even be better than good soil. Foamed Cement Banking (FCB), a kind of light material, is mainly discussed. Possessing of the good qualities on flowability, self-hardening, construction and economy, FCB gets a very wide application foreground.The substantial behavior of the FCB material is introduced thouroughly in this paper. Generally, the apparent density ranges between 500 and 1500 kg/m3 while the compression strength varies from 0.1 to 1.5MPa. Because FCB is fluid and self-hardening, the flow value is often controlled at about 180?0mm. The apparent density of FCB has an increasing of about 8 % atter immersion. The compression settling of FCB itself can be ignored in practice. The flexural strength is in a proportion of about 1/3 to the one-axis compression strength and the effect on strength can be ignored.The specific design theory for the FCB material when it was applied in the design of embankment and etc. was also presented in the paper. In specific design, the following loading factors should be taken into account: back soil pressure, water pressure, dead weight, overburden, horizontal soil force, buoyancy, seismic force and impact force. The different safety factors under different conditions should also be considered. The items concerning the stability can be divided into two aspects, for example, internal stability and external stability.Furthermore, the actual application of the FCB is introduced in the paper. The mix design of FCB should be performed according to the design conditions before construction. In the design, the properties of raw soil, the apparent density and strength of light soil, the flowability in construction and the resistance disassociation should be given. The following are the construction process steps: digging, preparing soil drainage andwater-proof project retaining wall works foaming, mixing and agitating transferrin placing, layin curing maintenance. The key point of FCB quality control is to make it clear whether FCB has reached its flowability and apparent density specified.It is obvious that the FCB material will get a very wide application foreground in future. FCB can be used for vertical filling to make the best of limited soil resource and to protect environment, for bank-filling on soft-base to control the post subsidence efficiently and to promote the stability and the security, for filling behind structures, such as abutment, to reduce the subgrade stress and to lessen the soil pressure supported by the back of the structures as much as possible by lighten the embankment greatly with the ultimate object is to improve the structures' using safety factor and to prolong the using life, and then to eliminate the jumping at bridge-head.A new method and concept are presented in the paper for the settlements of the problems in road construction, which includes soft-base treatment, jumping at bridge-head and pavement widening.