Study On The Effect Of Inorganic Curing Agent On The Structure And Properties Of Fluid Cured Soil

As a traditional building material,raw soil material has the advantages of environmental protection,low carbon,renewable,and good heat insulation,but there are still problems such as strength and durability performance to be improved,and the ramming and molding process is time-consuming and laborious.In this thesis,raw soil and building slag were used as raw materials,and the raw soil or building slag was cured by using cooked lime,cement,fly ash,metakaolin and slag in single or compound mixture,respectively,to study the workability of fluid cured soil,microstructure,mechanical properties,durability performance and thermal insulation performance of hardened cured soil specimens,and reveal the curing mechanism through the constitutive relationship,which provides a new path for the utilization of raw soil and building slag.The experimental results show that:The single and compound blending of inorganic curing agent helps to improve the mechanical properties and volume stability performance of raw soil materials,and the cured soil mix meets the demand of on-site pouring when the water reducing agent is blended at1.5%and the water-solid ratio is 0.20.The strength of the cured soil mixed with 10%slaked lime alone has the largest increase,and the strength of the cured soil specimen mixed with10%slaked lime+15%cement reaches 9.88 MPa,but the shrinkage is larger;the strength of the cured soil specimen mixed with 10%slaked lime+15%slag has good performance,low shrinkage,and the best comprehensive curing effect.The mechanism of action is due to the Ca（OH）₂in the slaked lime can fill the original loose raw soil,and hydration reaction with the active silicon and aluminum material inside the raw soil,generating hydration cementation products,bonding with each other and soil particles,changing the soil structure and improving the strength of cured soil;when compounded with slaked lime+mineral admixture,as the volcanic ash material can occur secondary hydration reaction,can further provide cured soil strength growth.Construction residue,recycled micronized powder and fine aggregates,how to efficiently resource utilization,is also an urgent problem to solve.In this paper,the effect of inorganic curing agents on the structure and properties of partially recycled micronized replacement construction residue was also investigated and compared with the properties of raw soil.The results show that the single and compound blending of inorganic curing agent helps to improve the mechanical properties and volume stability performance of construction residue materials.When the fixed water reducing agent was 0.5%and the water-solid ratio was 0.20,the cured slag soil mix met the requirements for on-site pouring.Compared with the cured raw soil,the amount of water reducing agent of slag soil is less.When 15%slaked lime is mixed with cement/mineral admixture alone,the strength of cured slag soil has the greatest growth;when slaked lime is compounded with cement/mineral admixture for curing construction slag materials,the strength performance of cured slag soil specimen with 15%slaked lime+15%cement has the greatest strength of 13.3 MPa,but the shrinkage rate is larger;the strength of cured slag soil specimen with 15%slaked lime and 15%slag is 10.58 MPa,and the shrinkage rate is lower The overall macroscopic performance of the cured slag is the best.The overall strength performance of cured slag is slightly higher than that of cured raw soil.Inorganic curing agents can effectively improve the durability and surface barrier capacity of the cured raw soil/slag,of which the cured raw soil/slag specimens with compounded slaked lime+cement have the best durability and the lowest water absorption rate of 25%.The original porous structure of raw soil ensures its excellent thermal performance,and the thermal conductivity of cured soil increases slightly after adding inorganic curing agent,but it is still close to that of pure raw soil,with good thermal insulation performance;the construction slag itself contains more bricks and concrete slag impurities inside,and the thermal conductivity is higher than that of pure raw soil,and after mixing with inorganic curing agent,the hydration product with higher thermal conductivity is generated inside,and the thermal conductivity of cured slag is increased again.The thermal conductivity of cured slag soil is increased again,and the thermal insulation performance is poor compared with that of cured raw soil.This study provides the basis for the scientific application of inorganic curing agent in fluid curing soil.