Study On The Performance Degradation Of Limestone Cement Mortar And Concrete Attacked In The Magnesium Environment Based On Analysis Of The Pore Structure

Process of crushed stone and artificial sand production produced limestone powder, which seriously effecting our living environment. Now limestone powder was effectively used in concrete, and many countries had put into action, and achieved good results. However, the durability of limestone concrete was exposed, in this paper; the properties of limestone concrete at sulfate attack environment were studied.In this paper, considering structures eroded under different Mg SO4 environment, using environmental simulation test: long-term immersion test simulated building structures under long lasting erosion; drying-immersion cycles simulated building structures located water table and splash zone area.Based on MIP of limestone cement mortar at Mg SO4 environment, the distribution of pore structure of limestone cement mortar were investigated, under Mg SO4 environment for long-term immersion and drying-immersion cycles erosion, then corresponding sub-porosity of all levels aperture of the limestone cement were calculated, and the effect of anti-corrosion performance changes between different amount of limestone, and erosion mechanisms. While using superposition modified, fly ash was incorporated. The results showed that: the double-doped limestone-fly ash mortar specimens significantly improved the durability of limestone mortar.Aiming at Mg SO4 drying cycle erosion environment, considering the affection of water-cement ratio, limestone powder content, and magnesium sulfate concentration, stress-strain characteristics were tested,in different water-cement ratio, limestone powder content, and Mg SO4 concentration. The results showed that: the stress-strain curve of limestone concrete were similar in different water-cement ratio, limestone powder content, Mg SO4 concentration, through numerical analysis, a corrosion rate model of limestone concrete was established,based on magnesium sulfate leaching solution drying cycle environmental erosion, in different water-cement ratio, limestone powder content, and Mg SO4 concentration.Considering actual building concrete materials in certain stress state, using the lab environment simulation, research about the peak stress, peak strain, modulus of elasticity and resistance to corrosion coefficient of limestone concrete was carried out, eroded by the stress of environment and magnesium sulfate coupling, then getting the influencing of stress and Mg SO4 environmental on each parameters variation of limestone concrete.