Experimental Study Of The Waste Cooking Oil On The Shrinkage And Durability Performance Of The Alkali-activated Slag Concrete

Alkali-activated slag concrete has good physical properties compared with conventional concrete.However,the shrinkage performance is larger than conventional concrete.The initial setting time of alkali-activated concrete is shorter,which has seriously restricted the construction site application of alkali-activated slag concrete.Waste cooking oil,commonly known as hogwash oil,has been produced in a huge amount each year in China,which has caused a great harm to environment.At the same time,a large part of the hogwash oil is returned to the table,which has great harm to human health.Some scholars applied it to conventional concrete.In this paper,the topic is based on that by applying the waste cooking oil,which act as a shrinkage reduction agent into the alkali activated slag concrete,and is considered to overcome the two main problems of alkali-activated slag concrete.One is making rational use of waste cooking oil,the other one is reusing waste into and reducing the practical project cost.Instead of using the commercial available expansion agent or the shrinkage reducing agent,this experiment use the waste cooking oil as the shrinkage reducing agent.The alkali-activated slag concrete experiment was conducted to study the effect of the waste cooking oil on the shrinkage and durability performances of the alkali-activated slag concrete.At the same time,the alkali-activated slag paste test was also conducted to explore the micro-structure of the slurry experiment.The detail of the study was illustrated as followed.(1)The alkali-activated slag mortar experiment was divided into 12 groups.Each group owns 3 pieces.The total number of the specimens is 36.The alkali-activated slag mortar experiment was conducted to investigate whether the waste cooking oil can reduce the shrinkage of the alkali-activated cementitious material.At the same time,the water-cement ratio of the alkali-excited of mortar was changed(the water to cement ratio was 0.3 and 0.5)to determine the effect of the oil shrinkage reducing agent on the shrinkage performance of the alkali-activated slag mortar.The experimental results show that the waste cooking oil has a shrinking reducing effect on the alkali-activated slag mortar.(2)The alkali-activated slag concrete experiment was divided into 12 groups with a total of 396 specimens.The concrete experiment was carried out by changing the types of the oil(emulsified,non-emulsified,edible oil,waste oil)and dosage(2%,4%).The relative between autogenous shrinkage and drying shrinkage ofalkali-activated concrete by applying different shrinkage-reducing agents was studied.The influence of different shrinkage reducing agents on mechanical and durability properties were also studied.(3)Microstructure analysis of alkali-activated slag paste by mercury intrusion experiment and SEM was also studied.The influence mechanism of shrinkage reducing properties were explained by the microstructure analysis.