Application Research Of Casting Type Of Cement Fly Ash In Backfilling On Back Of Bridge Abutments And Culverts

Bridges,culverts (access) is the main highway structures,often because of problems of compaction technologies,compaction control,construction methods and choice of packing, in highway operation,occuring a different subsidence in backfilling back of abutment and bridge deck,leading to bridgehead bump.Casting type of cement fly ash with the appropriate group can easily cast to abutment site which is not easily compacted,low prices,without vibration and mechanical rcc,good orthostatic after consolidation,small side pressure to abutment,small self-compression subsidence,rigiding is much better than general subgtades,light,greatly reducing the filling load of embankment,reducing foundation stress,inhibiting subsidence,site displacement and destruction of soft subgtades,significantly reducing different subsidence near the connecting of abutments and subgtades. Therefore,it is of great practical value to systematicly study it.This paper systematicly studied material composition,physical performance,strength characteristics,shrinkage characteristics,consolidation characteristics and compressive modulus of casting type of cement fly ash which backfilled back of bridge abutments and culverts with.We proposed evaluation methods and evaluation indicators of consistency and strength and design methods of materials composition of casting type of cement fly ash which backfilled back of bridge abutments and culverts.Through the large number of systematical strength tests,we knew relationship law with dose of cement,admixture,the consistency,ages and strength of casting type of cement fly ash hardened paste.Through consolidation and shrinkage tests,we knew stability volume law of casting type of cement fly ash after hardening.Through compressive modulus test , we recommended range of 180-day compressive modulus,and established rough relations with compressive modulus and compressive strength.Through the construction of pilot project,summarizing and proposing key technologies of the convergence with subgtades,the warehouses,drainage,layered thickness and mixing in construction.Afer doing the technical and economic analysis of backfilling of back of abutments with casting type of cement fly ash,we knew that its economic and social benefits is quite significant,with advanced technology and feasibility.