Water-proof Silicone Coating For Aga Soil In Tibet

Aga soil is unique building material in Tibet.It's a kind of limestone mainly composed of calcium carbonate,silicon dioxide and clay.Aga soil has low strength and poor waterproof performance.The internal viscous material is easily washed by rain,and becomes rough and cracked under the conditions of sun,rain,wind erosion,freezing and thawing,causing damage to the civil engineering relics.Therefore,how to protect the Aga soil buildings is a problem that needs to be solved.At present,there have been related work on the modification of Aga soil,but these methods have certain defects,and there are few work to take waterproof protection for Aga soil.Organosilicon is an excellent waterproof material with low surface energy,good weather resistance,and good bonding force with soil,stone,brick and other building materials.This work first researched the microstructure and chemical composition of Aga soil.Then selected hydrogen silicone oil(PMHS)with 1.6%wt hydrogen content to waterproof the surface of Aga soil,and researched the influence of technological parameters on various application indexes.Finally,the properties of Agt soil treated by dodecyltrimethoxysilane(WD-10)were researched compared with PMHS.The work content and results are as follows:1.Research the chemical composition and microstructure of Aga soil.The main components of Aga soil are calcite and quartz.It is limestone with calcite as the main component.The main composition is Aga soil debris,Aga soil micrite and a few of clay.The internal pore structure of Aga soil is mainly composed of the capillary pores formed by stacking the particles of Aga soil and the cracks distributed in the soil.The pore parameters of the Aga soil were measured with constant velocity mercury intrusion and Micro CT.2.To study the hydrophobicity of the surface of Aga soil coated with two kinds of silicone coatings.The main influencing factor of hydrophobicity is the humidity.When the humidity is lower than 90% RH,the higher the humidity,the better the hydrophobic performance.the longer the curing time,the better the hydrophobic performance.Longer curing time also increases hydrophobicity.Under the right conditions,both coatings can make the surface of Aga soil superhydrophobic.3.Research the permeability of organosilicon coating in Aga soil.Compared with PMHS,the penetration rate of WD-10 in Aga soil is faster;when the amount of coating is small,the penetration depth of WD-10 is greater than that of PMHS under the same coating dosage.When the dosage is large,the penetration depth is similar.4.Research the color change of Aga soil surface before and after applying organosilicon coating.Under the same amount of coating,the surface color change of Aga soil coated with WD-10 is small,which can better maintain the original appearance of Aga soil sample;while the surface color change of Aga soil coated with PMHS is relatively more obvious.5.Research the various properties of organosilicon-treated Aga soil.The samples have good water stability,coating adhesion and UV aging resistance.The samples treated with WD-10 also have good air permeability and abrasion resistance,but the friction coefficient will be obvious reduce.