###### Abstract  
In this study, three different models were developed to predict the compressive strength of SCC, including the nonlinear relationship (NLR) model, multiregression model (MLR), and artificial neural network. Thus, a set of 400 data were collected and analyzed to evaluate the effect of seven variables that have a direct impact on the CS, such as water to cement ratio (w/c), cement content (C, kg/m\({}^{3}\)), gravel content (G, kg/m\({}^{3}\)), and content (S, kg/m\({}^{3}\)), fly ash content, (FA, kg/m\({}^{3}\)), superplasticizer content (SP, kg/m\({}^{3}\)), and curing time (t, days) up to 365 days. Several statistical assessment parameters, such as the coefficient of determination (R\({}^{2}\)), root mean squared error (RMSE), mean absolute error (MAE), and scatter index (SI), were used to assess the performance of the predicted models. Depending on the statistical analysis, the median percentage of superplasticizers for the production of SCC was 1.33%. Furthermore, the percentage of fly ash inside all mixes ranged from 0 to 100%, with 1 to 365 days of curing and sand content ranging from 845 to 1066 kg/m\({}^{3}\). The results indicated that ANN performed better than other models with the lowest SI values. Curing time has the most impact on forecasts for the CS of SCC modified with FA. S +
Footnote †: journal: Applied Sciences  
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Footnote 1: institutetext: Department of Physics, University of Sulaimani, Sulaymaniyah 46001, Iraq  
Fly ash (FA) is a siliceous or aluminosilicate particle that has been finely divided. When moisture is present, it chemically combines with the calcium hydroxide generated when Portland cement hydrates to create a compound with cementing properties [5]. As a byproduct of burning pulverized coal, FA is a finely split residue produced in coal-fired power plants. The coal is crushed and blown into the burning chamber, where it burns right away to heat the boiler tubes. Regarding the influence of fly ash on self-compacting concrete (SCC) properties, a study indicates that a high volume of fly ash can be used in SCC to produce high-strength and low-shrinkage concrete. [PERSON] et al. compared hardened properties of normal concrete (NC) and self-compacting concrete (SCC) [6]. While most of the impurities deposited in coal during its formation, such as clay, shale, quartz, and feldspar, typically fuse and stay suspended in the flue gas, the volatile matter and carbon are burned off. The importance of a low water-cement ratio for enhancing the durability of concrete has long been accepted. Low water content leads to low workability of the fresh concrete; if this concrete is not properly compacted, the durability of the structures will be impaired. In the mid-1970s, superplasticizers were introduced to the market to produce rhinoplastic concretes [7; 8]. The flaming material is swiftly transferred to cooler regions, where it is formed into sphere-shaped particles. Lighter ash particles (FA) stay suspended in exhaust gases while heavier ash particles fall to the bottom of the burning chamber. Mechanical separators, electrostatic precipitators, or bag filters are used to remove these FA particles [9]. Previous research has shown that using mineral admixtures such as fly ash in concrete mixes can improve the slump without increasing expense while lowering the amount of superplasticizer needed to achieve equal slump flow when compared to concrete prepared only with Portland cement, and the presence of the fly ash lessens the heat of hydration and increases the durability [10]. Due to its finer and more rounded particles than cement, fly ash can be used to replace cement in the creation of self-compacting concrete. Fly ash could operate as a filler to cover the inter-particle spaces that cement is unable to occupy by making use of these physical features [11]. SCC consists of similar components to conventionally vibrated concrete: cement, aggregates, water, mineral, and chemical admixtures.