# Study on the Performance of Foam Concrete Prepared from Decarburized Fly Ash
## 1 Introduction  
In the current global warming situation, countries have searched for methods and established systems in the fields of construction and industry to reduce CO\({}_{2}\) emissions and achieve low-carbon sustainable development. China has also adopted policies such as the \"Healthy Building Evaluation Criteria\". Improving the resource utilization rate of construction waste is one of the concerns in China. In response to the policy of low-carbon environmental protection and technological innovation, this study uses decarbonized fly ash to prepare foam concrete for the purpose of green recycling and other uses. Foam concrete is a new type of thermal material, formed by mixing ng foam with cement and then cast-in-place after mixing with other mixes. The density of this concrete is between 100-2000 kg/m\({}^{3}\) and the thermal conductivity is generally around 0.1 W/(m\(\cdot\)k). Compared to ordinary concrete, it is lighter in weight with a better thermal insulation performance and is conducive to long-distance transportation. Its workability is related to the interaction between its blowing agent and cement [1]. F.K. [2] prepared foam concrete using cement, expanded vermiculite powder and silica powder and conducted a study on its dry and wet density, water absorption, ultrasonic, compressive strength and thermal conductivity. The results showed that the compressive strength of the foam concrete ranged between 0.4 and 3.7 MPa, the density ranged between 587 and 1040 kg/m\({}^{3}\), and the thermal conductivity ranged between 0.059 and 0.237 W/(m\(\cdot\)k). [PERSON] [3] prepared foam concrete by adding insulation and nanoporous aerogel to the foam concrete with a density of 198 kg/mand thermal conductivity of 0.049 W/(m\(\cdot\)k) for a new aerogel foam concrete. It can be seen that foam concrete has excellent insulation properties. However, at the same time, the foam concrete itself also has certain problems: low strength, large shrinkage and easy to crack. In the process of preparing foam concrete from decarbonized fly ash, the utilization of fly ash can also be a further concern. In terms of our environment-energy relationship, our electrical energy comes from coal combustion [4]. According to statistics, in 2020, China's coal-fired power generation accounts for 50.2% of the global total, and fly ash emissions are also upwards of 50%, both of which rank first in the world. From the global utilization of fly ash, the utilization rate of fly ash is 25%. Among them, India is 38%, the United States is 65%, and China is 45%. It can be seen that an increasing number of researchers in China are gradually paying attention to the comprehensive utilization of fly ash, which has in turn been strongly supported by the state. At present, the utilization of fly ash in China is mainly used in the fields of construction materials, agriculture, roads and mine rehabilitation, etc., 1. In building materials: [PERSON] [5] found that the partial replacement of cement with fly ash is helpful for high-temperature construction in China. [PERSON] [6] found that when the fly ash admixture is 15%, the 7d strength of concrete can reach 20 MPa and the 365d strength can reach 47.7 MPa. 2. In agriculture: It can improve the acidity and permeability of the soil, whilst reducing the swelling rate of the soil. It can also effectively consume the fly ash piled up and landfilled, alleviating the pressure on land and environment. 3. In the road: when the fly ash admixture is between 0% and 60%, its strength decreases with the increase in fly ash. However, when the fly ash admixture is within 40%, it can meet the compressive strength requirements of the road [7]. In addition, when the admixture is 15-30%, its 28 day compressive strength is 50.8 MPa, which can be used as asphalt pavement [8]. In addition to the three aspects described above, fly ash can also be used as an external admixture for special concrete to improve the performance of such concrete.