Research On The Method Of Measuring Chlorine In Co-Ncrete Based On LIBS

Reinforced concrete is a very important building material,because it is strong,durable,good fire performance,compared with steel structure,it saves steel and low cost.As early as the 18th century,it began to be used as a material for construction,port,bridge and other structural engineering.However,chloride ion corrosion will lead to the corrosion of reinforced concrete and seriously affect the life of concrete structure,so the detection of chloride ion concentration in concrete is particularly important.However,the traditional detection methods usually take a long time,and can not achieve real-time detection on site,which brings inconvenience to the evaluation of chloride corrosion degree of concrete.Therefore,in recent years,many researchers use laser-induced breakdown spectroscopy to determine chlorine in concrete.Laser Induced Breakdown Spectroscopy(LIBS)is a method of atomic emission spectrometry that is to focus directly on the sample with high-energy Laser pulse,so as to induce the plasma of the sample.This technique is based on the interaction between laser and material,which can accurately analyze the composition and content of material from the perspective of physics and spectroscopy.Based on the above problems,this paper in the first instance uses PrismSPECT to simulate the chlorine spectrum line,through the simulation of the chlorine spectrum line,the conclusion is that with the increase of temperature,the intensity of the spectrum line gradually decreases.With the increase of mass density,the intensity of C1 I line increases gradually.In the next place,the detection mechanism of nonmetallic element Cl in LIBS system based on picosecond laser is studied in this paper.The main purpose is to provide reference and technical support for the evaluation of the corrosion degree of the LIBS technology in the seaside concrete buildings.In this paper,the construction of LIBS system based on picosecond laser was completed,and the best experimental parameters were obtained through experiments:the best experimental spectral line C1 I 837.6 nm was selected,200 ns was selected as the daylighting delay,and helium was used as the detection gas atmosphere.In the end,using the established test platform,this paper completed the LIBS detection on the surface and penetration surface of samples with different immersion time,and explored the influence of different immersion time on chloride ion penetration.At the same time,the permeability curves drawn by LIBS detection and chemical titration were compared to determine the critical penetration depth of different samples.The LIBS system based on picosecond laser and the detection method of chlorine in concrete established in this paper provide a theoretical basis for the field detection of concrete corrosion in the future.