Influence Research Of Waste Concrete On Durability Of GRC

Construction waste has accounted for 80%-90%of the total amount of city waste in our country,but resource utilization rate is less than 5%,waste concrete accounts for 30%-40%of construction waste.Thus,how to effectively deal with these building waste has become a subject we must face,besides,it is crucial to realize resource reutilization.GRC has many advantages,such as light weight,crack resistance,impact resistance and so on,but GRC has the problem of long-term durability which limits the field of application.In order to heighten the recycling rate of waste concrete and improve the long-term durability of GRC,waste concrete was applied to GRC,and the influences of waste concrete on the durability of GRC are analysed.The research mainly solves the following problems:①Research the influences on the properties of GRC by using waste concrete aggregate to replace the naturalsand and adding fly ash and silica fume to replace ordinary Portland cement in GRC.② Research the influences on the properties of GRC when the ordinary Portland cement is replaced by different fineness waste concrete powder.③ Research the influences on the properties of GRC by using waste concrete powder,fly ash and silica fume to replace ordinary Portland cement in GRC.④Research the influences on the properties of GRC by using waste concrete aggregate and waste concrete powder to replace the natural sand and the ordinary Portland cement respectively.The results show that:①It is effective to improve the durability of GRC by using waste concrete aggregate.The experiment group using 30%waste concrete aggregate to replace the natural sand shows better durability than reference group.And using 30%fly ash or 20%fiy ash and 10%silica fume to replace ordinary Portland cement,the durability of GRC has been enhanced greatly than the experiment group using 30%waste concrete aggregate.②It is ineffective to improve the durability of GRC by using 10%waste concrete powder to replace cement,and with the curing age extending,the eroded degree of glass fiber is more serious,leading to the reducing of the durability of GRC,and the waste concrete powder is finer,the eroded degree of glass fiber is more serious,and the reducing range of durability of GRC is bigger.③Natural sand and cement are replaced by 30%waste concrete aggregate and 10%waste concrete powder respectively,the durability of GRC has been enhanced greatly than the experiment group using 10%waste concrete powder,but has been reduced greatly than the experiment group using 30%waste concrete aggregate.It can be seen from the eroded degree of glass fiber,the glass fiber of the experiment group using 10%waste concrete powder is the most serious,the glass fiber of the experiment group using 30%waste concrete aggregate is lightest,the two experiment complex,the eroded degree of glass fiber is between the two.④Using 30%waste concrete aggregate and 30%fly ash or 20%fiy ash and 10%silica fume to replace natural sand and cement respectively,the durability of GRC has been enhanced greatly than reference group and the experiment group using 30%waste concrete aggregate,the eroded degree of both glass fibe is alleviated obviously.⑤Using 10%waste concrete powder and 30%fly ash or 20%fiy ash and 10%silica fume can improve effectively the durability of GRC,and they have better effect than the experiment group using 10%waste concrete powder,at the same time,theeroded degree of glass fiber is alleviated obviously.⑥Using 30%waste concrete aggregate to replace natural sand,the degree of crystallization of CH and the eroded degree of glass fiber have been alleviated greatly than reference group.Using 30%waste concrete aggregate and 30%fly ash or 20%fiy ash and 10%silica fume to replace natural sand and cement respectively,the degree of crystallization of CH and the eroded degree of glass fiber have been alleviated greatly than the experiment group using 30%waste concrete aggregate.⑦ Using 10%waste concrete powder to replace cement,the degree of crystallization of CH and the eroded degree of glass fiber have been enhanced obviously than reference group.Using 10%waste concrete powder and 30%fly ash or 20%fiy ash and 10%silica fume to replace cement,the degree of crystallization of CH and the eroded degree of glass fiber have been alleviated greatly than the reference group.