Experimental Study On The Compressive Property Of Cement Modified Soil Blocks

With the gradual elimination of clay bricks in the walls of ordinary residential houses and the continuous development of new green materials research,cementmodified earth blocks came into being.It is a green material with broad development prospect and application potential,especially in housing construction projects,with the advantages of high load-bearing capacity,energy saving and environmental protection,cost saving,recyclability,etc.Therefore,in order to make the blocks work in the walls of ordinary residential houses,a comprehensive and systematic experimental study should be conducted.In this paper,the soil of Hefei West Station was used as the research object,and specimens made by adding different dosing cement and watercement ratio were maintained for different times for unconfined compressive test and shear test,and their unconfined compressive strength and shear strength were studied.Combined with the results of single-factor and multi-factor tests,the analysis from the viewpoint of practicality and economy found that the water-cement ratio of 0.45 with 15% and the water-cement ratio of 0.55 with 20% of the appropriate cement dose at the curing age of 28 d.The strength of the specimens made of these two groups of ratios is larger and can also better reflect the effect of the water-cement ratio as a variable mixed with cement on the specimens.Therefore,according to the specification,blocks and masonry with different mix ratios were prepared and the damage process and strength properties were analyzed according to the compressive test.The study found the following:(1)In the single factor test,it was observed that as the cement admixture gradually increased from 0% to 10% with low cement admixture,the unconfined compressive strength and shear strength of cement modified soil grew more slowly.In addition,as the cement admixture increased from 10% to 15%,the interaction force between cement particles was enhanced,which promoted the cement hydration reaction,resulting in increased adhesion between cement particles and aggregates and faster growth of unconfined compressive strength and shear strength.However,as the cement admixture exceeds 15%,too many cement particles are gathered together,resulting in smaller voids between cement particles,insufficient hydration reaction,and the rate of strength increase decreases,and finally tends to stabilize gradually.(2)In the orthogonal test,it was found that the unconfined compressive strength,cohesion and internal friction angle of cement-modified soil blocks were positively correlated with cement admixture and curing age,and negatively correlated with watercement ratio by extreme difference analysis.Further analysis of variance revealed that cement admixture had the greatest effect on strength,followed by water-cement ratio and the minimum age of curing.(3)In the masonry compressive test,it was observed that the damage process went through different stages,and the damage mechanism was also analyzed;through the test data and theoretical analysis,the compressive strength calculation formula applicable to the raw earth mortar block masonry was derived,and it was compared and analyzed with the experimental data,and the results showed that the theoretical calculation results were in good agreement with the experimental results and could be applied to engineering practice.