Foam concrete machine for backfill foundation pit

Traditionally excavations were filled using granular materials, usually crushed stone. The major problem with such materials is compaction. Not only is it impossible to achieve full compaction during reinstatement, but problems occur at the edges of trenches where the compactor will not fit. It is also impossible to compact around other services without causing damage. After surfacing, settlement of the backfill material occurs due to trafficking, only reaching full compaction after six months, when the road surface has to be re-excavated, and a new surface laid.

Now, foam concrete is one kind of very popular material for backfill foundation pit. Why foam concrete is the best choice?  The new specifications demanded that the backfill materials fulfil the following criteria:

(i)  The fill material should require little or no compaction, and should not settle after placing.

(ii)  It should not transmit axle loadings directly to the service in the trench.

(iii) Final resurfacing should be possible almost immediately, and there should be no need to revisit the site to

replace the surface at a later date.

(iv) The technique should be economic.

(v)  The material should be readily available.

(vi) The material should permit easy re-excavation.

(vii) The technique should be easy to perform.

(viii) The material should be suitable for filling narrow trenches.

Since foamed concrete fulfils all of theses criteria, it is a very suitable material for trench reinstatement, and backfil foundation pit, and has been successfully used for this purpose by several utilities companies in China and some other countries in Asia.

From all the work conducted so far, it is clear that not only is foamed concrete a suitable alternative to the traditional granular backfill materials, but it is also significantly better, providing a more stable, longer lasting reinstatement.