模拟酸雨对砂浆的强度、物相和孔结构影响的研究

INFLUENCE OF SIMULATED ACID RAIN ON STRENGTH, CRYSTAL AND PORE STRUCTURES OF SAND LIME SLURRY

Influence of simulated acid rain of different acidity and SO₂₊-4 concentration on sand lime slurry was examined by using two erosion accelerating methods (periodical immersion and periodical spraying). It was found that the strength of sand lime slurry reduces by the erosion, and the reduction is a bilinear function of CaO content and the ratio of SO₃ to CaO in the eroded test samples. The erosion effect of H⁺ results in the loss of CaO, MgO, Al₂O₃ and Fe₂O₃ in sand lime slurry. The coordinate erosion of H⁺ and SO₂₊- 4 causes to increase in the ratio of SO₃ to CaO. The main reason for significant decrease in sand lime slurry strength is that the crystal structures such as 408, KAl₂Si₂O₈ and 0.62NaAl₂SiO₈·0.38CaAl₂ transform to CaSO₄·2H₂O, CaAl₂Si₂O₈, Ca-Fe-Al-S-Si-O, and even more voluminous Ca₃Al₆O₁₂ ·CaSO₄ as the result of erosion, leading to an increase in porosity and bad pore size distribution. Therefore, the main cause of erosion of sand lime slurry by acid rain is dissolving erosion by H⁺ and expanding erosion by SO₂₊- 4.