Study On Mechanical Properties And Modification Of Hydraulic Lime In Different Curing Environment

China has a long history,there are many precious ancient buildings,which are full of historical value artistic value and non renewable resources.Up to now,most of the ancient buildings is sandstone,such as grottoes,ancient walls and so on.In many factors,water is an important factor for ancient buildings to long-term preservation.Due to geographical location,the time of the ancient buildings in wet environment is different.Therefore,using materials to meet the needs of the actual restoration of cultural relics to repair and strengthen the ancient buildings,which is conducive to the preservation of ancient buildings for a longer time.Hydraulic lime has the advantages of good permeability and compatibility with cultural relics,which is widely used in cultural relic restoration engineering.However,the hydraulic lime used in engineering depends on imports,and the demand in China is large.Therefore,using potassium feldspar and limestone as raw materials to prepare hydraulic materials similar to the composition of hydraulic lime,the gas hardness content of Ca O is 30% and the water hardness is content of C2 S is 26%,studying the influence of curing methods on the mechanical properties of hydraulic lime.Analyzing the influence mechanism of curing method on mechanical properties of water-hard lime with micro-morphology.The compressive strength of the specimens natural curing 28 d is 3.64 MPa,which meets the European standard for hydraulic lime NHL3.5.The compressive strength of the specimen natural curing 21 d is 3.07 MPa,and the stress-strain curve has obvious elastic deformation stage and yield stage and a stable strain localization zone is formed at the peak load,and the maximum horizontal strain value at the peak load is 0.083.The compressive strength of the specimens after 14 d of dry curing is 2.74 MPa,the stress-strain elastic deformation stage and the yield stage are short,and the maximum horizontal strain value at the peak load is 0.07,because the carbonization reaction in the early stage can not be carried out fully,cause the silicon rich layer near the C2 S nucleus to be relatively weak.The C-S-H microstructure produced by hydration is smaller and smaller than that of natural curing,casing the deformation resistance of the specimen is reduced.After wollastonite is mixed with hydrohard lime,the pozzolanic reaction can enhance the effect.The unreacted wollastonite particles are filled into the pores of hydrohard mortar to reduce the porosity and improve the mechanical properties of hydrohard lime.The increase of wollastonite content is not conducive to the increase of compressive strength of hard lime.The compressive strength of water-hard lime mortar with 10% wollastonite content curing 28 d under natural conditions is 5.28 MPa,the stress displacement curve is similar to the linear type,has no yield stage,and showing brittle characteristics.The deformation distribution is dispersed and the deformation is small before the peak load.A large number of gully inclusions formed by volcanic ash reaction will reduce the porosity of the sample and increase the compressive strength,but it will reduce the contact area with sandstone block and reduce the bond strength.In this thesis,there are 51 pictures,14 tables and 88 references.