Research On Road Performance Of Cement Stabilized Nickel Chromium Slag

Tongliao is rich in nickel chromium resources,resulting in much nickel chromium slag.In recent years,the state has made great efforts to develop road traffic and the nickel chromium slag can be applied to it,which not only deals with industrial waste reasonably,but also provides a new material for highway traffic construction.The nickel chromium slag is made as the research object in the paper.First of all,measure its chemical composition content and the basic index.Then the screening test is conducted and find that the composition of the particles is poor.So the slag is divided into three grades to redesign the grading.Then the compaction test of the cement slag mixture is conducted to determine the optimum moisture content and maximum dry density for different cement contents,which provides the basis for subsequent tests.Research on road performance of the cement slag mixture for three aspects:(1)Mechanical properties: unconfined compressive strength test,indirect tensile strength test and compressive resilience modulus test of the mixture are made.And the tests show that the cement content to meet strength requirements is 5% and 6%.The main influencing factor of early unconfined compressive strength is age and the later of it is cement content.Both the indirect tensile strength and the compressive rebound modulus increase with the growth of the cement content.The stress and strain of the former specimen increase with the growth of cement content.The stress-strain curves of the latter specimen become more dense with the growth of cement content and the elastic deformation increases with the growth of the cement content,which reflects the increase in stiffness from the side.(2)Durability: the shrinkage test,the temperature shrinkage test and the freeze-thaw test of the mixture are made.The tests show that the shrinkage loss rate decreases with the growth of cement content.While the dry shrinkage,the shrinkage strain,the shrinkage coefficient and the average shrinkage coefficient increase with the growth of the cement content.The cement content should be limited when the strength requirement is satisfied.The temperature shrinkage strain increases linearly with the decreasing of the temperature.The temperature shrinkage coefficient shrinks up and down with the temperature decreases.It increases with the growth of cement content,and it reaches a minimum around 0°C.Through the freeze-thaw test,the strength and quality of the test specimens are found to decrease,but the decrease is small.The mass loss rate increases linearly with the times of freeze-thaw cycles.(3)Microscopic examination and strength analysising: the tests show that the microscopic interfaces of samples with different cement contents are similar.In the early products,there are less C-S-H and AFt.With the growth of age,the C-S-H and AFt are interweaving to form a network.The structure glues the particles together to form a whole.By comparing the chemical composition content of nickel chromium slag and crushed stone,find that they are same in the main chemical composition.They are acidic and their activities are strong.The strength formation includes three aspects: physical-mechanical,chemical and physical-chemical.The strength of the slag particles and mechanical compaction provide the initial strength.The hydration of cement is the main source of strength.