Properties Of Cement-based Foam Concrete Containing Silt

Bump at bridge-head is one of the most common problems in highway construction.It affects the driving comfort seriously,reduces the speed of the vehicle and the road capacity,and is one of the major hidden dangers in road traffic safety,which damages the social benefits of the highway and Economic benefits.Moreover,the extensive maintenance and repair of the bridge pavement not only cost a lot of manpower and material resources,but also bring up the malaise insociety.The problem of bump at bridge-head has become an obstacle to the improvement and speeding up the quality of highway construction,and it is also a major challenge for engineering staffs.It have great significance for improving the social benefits of roads,reducing the cost of maintenance and repair of roads that have already been built,and improving the quality of roads to be built that how to control the bump at bridge-head effectively,ensure the road safety and ride comfort.At present,many new lightweight materials have been used for subgrade backfilling,and have achieved good results,among which the performance of foamed concrete' materials is more prominent.The Cement-based foam Concrete Containing Silt proposed in this paper is also a kind of high-porosity material,which not only has the excellent performance of foam concrete' materials,but also have economical and environmental protection because of a large amount of silt incorporated.In this experiment,we use two processes,chemical preparation and physical preparation,that were used to study the serum fluidity and wet density,dry apparent density,compressive strength,CBR,and the static elastic modulus for various factors on cement-based silt light-weight fillers.We also studied natural drying shrinkage characteristics,water stability,dry and wet cycle characteristics,fluid loss characteristics,water absorption and microscopic morphology of the fillers.In the later stage,the effect of cement-based silt lightweight fillers with different specific weights on the consolidation settlement of foundations was analyzed by finite element software.The excellent properties of cement-based silt-based lightweight fillers were verified by engineering examples.The research shows that the properties of cement-based silt lightweight filler prepared by chemical method and physical method are very similar.In terms of mechanical properties,the unconfined compressive strength of Cement-based foam Concrete Containing Silts increases with the age of curing,and the larger the particle size of silt,the higher the strength of cement-based silt-based lightweight fillers;The greater the amount of soil,the lower the compressive strength,the flexural strength,and elastic modulus of the filler;the ratio of water to material or the water bath The curing temperature can increase the strength of Cement-based foam Concrete Containing Silts within limits.With the increase of air-entraining agent content,the wet bulk density,dry apparent density and compressive strength of Cement-based foam Concrete Containing Silts will decrease;The influence of the agent on the strength properties of the Cement-based foam Concrete Containing Silt is not obvious;the local bearing capacity of the filler gradually decreases with the increase of the silt content.In terms of durability,the wet and dry cycle durability of the filler is excellent,and the strength can maintain stable and grow steadily under long-term flooding conditions.Moreover,the greater the amount of silt,the greater the increase in strength of the specimens.In terms of pore structure and physical properties:With the increase of silt,the initial moisture content of the filler decreases faster;water absorption,true density,void content,dehydration rate and natural drying shrinkage increase with the increase of silt.By observing the microscopic appearance of the filler,it was found that the pores of the light-weight fillers of the cement-based silt can be classified into two types according to the pore size:150 to 100 ? m;150 to 200 ? m.The filler crystals were well crystallized on the seven days of hydration and were in the form of pins with needles.The incorporation of nano-CaCO3 in the filler can improve its compressive strength and flexural strength,reduce the rate of water loss and natural shrinkage.And with the increase of the particle size of the nano-CaCO3 particles within limits,the effect of enhancing the strength is enhanced.Increasing the amount of sand can improve the compressive strength of Cement-based foam Concrete Containing Silts and reduce the moisture content.