Study On Properties Of Copper Slag Powder-based Cementitious Materials Excited By Ca（OH）₂

In order to explore the hydration characteristics and mechanism of copper slag powder in cement mortar,and to further explore the influence of Ca（OH）₂ activator on the performance of copper slag powder-cement-based cementitious materials,the setting time and fluidity tests were conducted to study the content of copper slag powder and Ca（OH）₂.The effect of Ca（OH）₂ on copper slag powder-cement-based glue was studied through strength test,carbonization test,and sulfate corrosion test.The influence of the mechanical properties and durability of the cementitious materials,and the microscopic properties of the copper slag powder-cement-based cementitious materials were characterized by SEM and XRD,and the excitation effect and mechanism of Ca（OH）₂ on the copper slag powder cement system were systematically studied.Basic performance research shows that as the copper slag powder content increases,the cement setting time is prolonged.when the copper slag powder content is≥30%,the initial setting time can be extended by 168min at the longest,and the final setting time can be extended by 174min at the longest.The setting time of copper slag powder-cement-based cementitious materials decreases with the increase of Ca（OH）₂ content.With the increase of the amount of copper slag powder,the fluidity of 0,1.0,and 2.0 h of standing still showed a trend of first decreasing and then increasing and decreasing,but the range of change was not consistent.30%copper slag powder can significantly improve the initial fluidity of cement mortar.However,Ca（OH）₂ cannot significantly improve the fluidity of copper slag powder-cement-based cementitious materials.Research on mechanical properties and micro properties shows that:（1）The degree of hydration of pure cement mortar specimens increases with age;the hydration degree of each test piece mixed with 30%copper slag powder increased with the increase of age,but the compressive strength declined at 180d;in addition,the hydration activity of copper slag powder was lower before 28d,and the highest activity was at 90d.（2）Ca（OH）₂ is conducive to the development of the strength of copper slag powder-cement-based cementitious materials,and the optimal content is 2%.（3）Compared with pure cement mortar,in the specimens mixed with 30%copper slag powder,the characteristic main peak intensity of hydration products Ca（OH）₂ and C₂S is significantly reduced;in addition to Ca（OH）₂,dicalcium silicate（C₂S）,ettringite（AFt）and calcium carbonate（CaCO₃）in the hydration products of copper slag powder-cement-based cementitious materials,silica was also detected（SiO₂）and other products.（4）With the increase of age and Ca（OH）₂ content,the characteristic peak intensity of the reactants C₂S and SiO₂ in the copper slag powder-cement-based cementitious material decreases,and the characteristic peak intensity of the hydration product AFt increases.Research on anti-carbonization performance and micro-performance shows:（1）The incorporation of copper slag powder is beneficial to improve the anti-carbonization ability of composite cement mortar.（2）Ca（OH）₂activator promotes the anti-carbonization ability of copper slag powder-cement-based cementitious material,and the best content of Ca（OH）₂ is 1.0%.（3）Compared with uncarbonized,the hydration products of copper slag powder-cement-based cementitious material after carbonization are in addition to Ca（OH）₂,ettringite（AFt）,calcium carbonate（CaCO₃）,silicon dioxide（SiO₂）and aluminum oxide（Al₂O₃）,products such as hydrated calcium aluminum（iron）acid were also detected;with the increase of carbonization age and Ca（OH）₂,the characteristic peak intensity of Ca（OH）₂,SiO₂ and Al₂O₃ in the hydration product decreases,while the characteristic peak intensity of CaCO₃,AFt and hydrated calcium aluminum（iron）acid increases.Sulfate corrosion resistance and micro performance studies show that:（1）The incorporation of copper slag powder is beneficial to improve the sulfate corrosion resistance of composite cement mortar,and the addition of 1.0%Ca（OH）₂ is beneficial to the development of copper slag powder-cement-based cementitious material’s sulfate erosion resistance.（2）Before 30 days of sulfate attack,the quality of each test piece increased with age,and after 30 days of attack,it decreased with age.The effect of Ca（OH）₂ on copper slag powder-cement-based cementitious materials The change in outlook has no significant impact.（3）Compared with sulfate attack 0d,the hydration products after copper slag powder-cement-based cementing material corrosion are Ca（OH）₂,ettringite（AFt）,calcium carbonate（CaCO₃）,and silica In addition to（SiO₂）and aluminum oxide（Al₂O₃）,products such as gypsum（CaSO₄·2H₂O）were also detected;with the increase of corrosion age and Ca（OH）₂,the characteristic peak intensity of Ca（OH）₂,SiO₂ and Al₂O₃ in the hydration product decreases,while the characteristic peak intensity of AFt and CaSO₄·2H₂O increases.（4）When curing with clear water for 90 days,compared with sulfate erosion for 90 days,gypsum（CaSO₄·2H₂O）is mainly lacking in hydration products,and the characteristic main peak intensity of Ca（OH）₂ is obviously increased,and the characteristic main peak intensity of ettringite（AFt）is reduced.