| Steel slag is the waste discharged in the process of steelmaking.It is the solid waste with the largest emissions in the steel industry and also one of the solid wastes with the lowest comprehensive utilization rate at present.The massive dumping of steel slag and the pollution to the environment are also a waste of resources.In this paper,steel slag powder is used as auxiliary cementitious material to prepare ultra-high toughness cement-based composite material,which is expected to open a new way for rational utilization of steel slag.Two kinds of water-binder ratios of 0.25 and 0.35,and five kinds of steel slag powder dosage(respectively 0,20%,40%,60% and 80%according to the gradient)were designed.The mechanical properties and durability of PVA fiber reinforced cement matrix composites mixed with steel slag powder were studied through cube compressive strength test,direct tensile test and sulfate erosion test.The main research conclusions are as follows:(1)It is feasible to use steel slag powder to prepare ultra-high toughness cement-based composites.The PVA fiber reinforced cement-based composite mixed with steel slag powder provides a new way to solve the problem of massive accumulation of steel slag,and expands the new application space of steel slag in the field of construction,thus protecting the environment and realizing eco-friendly and green environmental protection.(2)The cube compressive strength test of PVA fiber reinforced cement-based composites mixed with steel slag powder was carried out.The results showed that the addition of appropriate amount of steel slag powder would enhance the compressive strength of cement-based composites.With the increase of steel slag powder,the cube compressive strength of cement-based composites decreased gradually.When the content of steel slag powder is less than 60%,the compressive strength of PVA fiber reinforced cement-based composite mixed with steel slag powder can still meet the needs of general engineering.From the perspective of compressive strength,when the content of steel slag powder is 20% and the water-binder ratio is 0.25,the strength of cement based composite mixed with steel slag powder reaches the best.Low water-binder ratio is more beneficial to the increase of compressive strength of PVA fiber reinforced cement matrix composites mixed with steel slag powder.(3)The tensile test of PVA fiber reinforced cementitious composites with steel slag powder was carried out.The results show that the addition of steel slag powder can significantly improve the tensile properties of cement matrix composites,and the higher the content of steel slag powder,the better the tensile properties of PVA fiber reinforced cement matrix composites with steel slag powder.The m25ss80 group has the best tensile performance.The maximum tensile strain at 28 d reaches 5%,which is 9.06 times of that of the reference group,and the ultimate tensile strain at 180 d reaches 4.744%,which is 7.87 times of that of the reference group.(4)The sulfate erosion test of PVA fiber reinforced cement-based composites with steel slag powder was carried out,and the results showed that the addition of steel slag powder could improve the corrosion resistance of cement-based composites,and the corrosion resistance coefficient of compressive strength gradually decreased with the increase of the steel slag powder content.In the test,the m25ss20 group has the best sulfate erosion resistance,and the specimen can still maintain good integrity when the erosion age reaches 90 d,and the corrosion resistance coefficient reaches the highest of1.06 among all groups. |
