# Study on Hydration Heat Release Model and Its Influence Coefficient of Addition Concrete
## 3 Numerical Calculation Model and Its Accuracy Verification
### Semi-Adiabatic Temperature Rise Test  
The semi-adiabatic test device comprises a concrete mold and an insulation box. The interior of the insulation box with internal dimensions 31 cm \(\times\) 31 cm \(\times\) 31 cm is lined with a 10-cm-thick polyurethane composite insulation board. Inside this arrangement, an internal concrete mold box with 21 cm \(\times\) 21 cm \(\times\) 21 cm sides with 1 cm thick polypropylene-sheet liner is set such that there is clear 20 cm \(\times\) 20 cm \(\times\) 20 cm internal space. For the accurate measurement of the core temperature of the concrete specimen block, temperature sensors with accuracies of \(\pm\)0.25 \({}^{\circ}\)C are embedded in the core part of the concrete specimen block during testing. An integrated test system is used to monitor the temperature change of the concrete continuously and automatically store the temperature data of the concrete specimen. The time interval setting for the temperature measurement command is set to 20 min. The test setup and arrangement of the monitoring instruments (CHN) are illustrated in Figure 2.  
Figure 1: Three-dimensional model and temperature cloud for semi-adiabatic temperature rise test.  
In large-volume concrete projects, additions are generally used to replace 20-70% of the cement [17], so in order to explore the influence of different additions on the temperature rise characteristics of concrete, the additions in this test are set to replace 40% of the cement. The concrete test block adopts the material ratio of common C40 concrete. Fly ash is a mineral admixture commonly used to reduce the heat of hydration in engineering [18]. The test was based on fly-ash, and the three remaining additive materials, viz., blast-furnace slag, limestone powder, and metakaolin, were added in various combinations. Different concrete specimens with double, triple, and quadruple additions were cast and the semi-adiabatic temperature rise tests were conducted separately for each specimen. The marking scheme for the specimens is as follows: F (fly-ash), S (blast-furnace slag), L (limestone powder), and K (kaolin); the number after the letter represents the percentage of cement replacement. For example, F20S20L0K0 indicates a concrete test-specimen block with 20% fly-ash and 20% blast-furnace slag, and the specific coordinates of all the test specimen blocks are listed in Table 3.  
Conduct of the semi-adiabatic temperature-rise test involved the following six steps: (1) Assembly of the customized polyurethane-lined insulation box and polypropylene concrete mold. (2) Accurate measurement of the ingredients according to the design ratios of different concrete test specimens and adequate mixing according to the mixing procedure and the test criteria. (3) The prepared concrete mix was poured into the polypropylene concrete mold and vibrated sufficiently. (4) Temperature sensors were embedded in the cores of the concrete specimens at predetermined intermediate locations. (5) Place the concrete specimens together with the mold in the preset insulated box and seal it. (6) The real-time monitoring system was connected to the monitoring system and the temperature data were extracted every 20 min. The concrete specimens were continuously monitored  
Figure 2: Semi-adiabatic temperature rise test setup and monitoring instruments. (**a**) Test setup. (**b**) Temperature sensor. (**c**) Real-time monitoring system.  
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Serial Number**} & **Cement** & **fly-ash** & **BF Slag** & **Limestone** & **Metakaolin** & **Medium** & **Coarse** & **Water** & **Superplasticizer** & **Volume** \\  & **(kg)** & **(kg)** & **(kg)** & **(kg)** & **(kg)** & **(kg)** & **(Stonen)** & **(kg)** & **(kg)** & **(kg)** & **(m\({}^{3}\))** \\ \hline F6S0L0K0 & 420.0 & 0.0 & 0.0  
for a period of approximately seven days, and the semi-adiabatic temperature-rise curve of the concrete specimens during the aging period was obtained.