Preparation And Properties Of Controlled Low-Strength Materials Produced By Construction Waste

With the continuous progress of the modernization process, a variety of basic construction projects will rise. In the process of construction of these projects will produce a large amount of construction waste, and will have many adverse effects on the environment.Controlled low-strength materials(CLSM) is a very common structural material that can be used in many engineering applications. It can recycle a lot of industrial by-products. In areas where the natural aggregate is limited or difficult to find the right place to deal with the excavated soil, the natural soil has been used to replace the aggregate to produce CLSM. This paper will use the construction waste as raw materials to produce CLSM. Through the use of materials like clay and silt from field construction which is not suitable for the backfill soil not only can reduce the production of construction waste, but also can reduce the occurrence of soil erosion and other issues.Considering the construction wastes may influence CLSM's workability, setting and hardening, durability and deformation properties. So in this paper, according to the above three points do the relevant research, discusses the influence of each component on the performance of CLSM. The experimental results show that use construction wastes can produce CLSM with suitable workability, strength in between 0.31 MPa 25.15 MPa and controllable, setting time is less than 24 hours and the settlement value is between 3.5mm/m and 2mm/m. The main conclusions are as follows:(1) Through the adjustment of fly ash, construction waste and sand ratio, CLSM with good flowability and the mixture of the bleeding rate in 2%- 5% can be prepared. Compared with the construction waste, fly ash has good ability to maintain flowability, but bleeding rate increased; increases slag and sand will increases the loss of flowability, and can reduce the rate of bleeding of CLSM.(2) The variation range of CLSM's 56 days compressive strength is between 0.31 and25.15 MPa. And its strength is controllable. By adjusting the dosage of construction waste,water reducing agent, tailings and cement can control the CLSM's strength. You can get the setting time of less than 24 hours CLSM; As long as no obvious segregation and bleeding occur through adjusting dosage of tailings and content of cement can control CLSM setting time.(3) CLSM's resistance to wet dry cycling ability is relevant to the dosage of construction waste; CLSM's resistance to freeze-thaw cycling ability is poor; the deformation properties were influenced by changes in dosage of water reducer, tailings sand, cement and fly ash.When the content of construction waste was low(10%), CLSM has a good anti wet dry cycling ability. CLSM has a poor ability to resist freezing and thawing cycles. Construction waste incorporation will lower CLSM's ability to resist natural drying shrinkage, but when the construction waste content is 30%, by adding construction waste can significantly improve the CLSM's resistance of 3 days after natural drying shrinkage deformation ability. The incorporation of tailings sand can enhance its ability to resist shrinkage and deformation;increasing cement content can not significantly improve the ability of CLSM to resist shrinkage deformation; fly ash replacement tailings will lower the ability to resist the shrinkage deformation of CLSM, slightly increasing CLSM's ability to resist natural drying shrinkage deformation. With the change of the content of tailings sand, the settlement value changes between 3.5mm/m and 2mm/m. The greater the amount of tailings sand content, the smaller the final settlement value, the shorter the time required to stabilize the settlement.