# Study on the Effect of Vibrating Process on the Compactness of Slipform Concrete
## 7 Conclusions  
(1) Under the effect of high-frequency vibrating, larger aggregate particle size caused a larger aggregate distribution coefficient value and a lower degree of uniformity. In addition, the value increased at a faster rate under the vibration liquefaction effect. The maximum size of the aggregate used should be reduced to improve the uniformity of the aggregate in the process of slipform paving and enhance the quality of slipform concrete paving and vibrating construction.  
(2) The vibrating parameters of the high-frequency concrete vibrating rod significantly influenced the compressive strength and SC value of the aggregate segregation rate of slipform concrete. Compressive strength increased and then decreased with the vibration time. In addition, the higher the frequency of vibration, the faster the rate of change. The rate of aggregate segregation increased with the vibration time, and the higher the frequency of vibration, the more it increased. The SC value of the segregation rate should be <0.15 to avoid adverse effects on the quality of concrete.  
(3) The effects of different vibrating parameters on different pore-size bubbles of slipform concrete were different. Large pore-size bubbles were predominantly discharged, the pore area inside the concrete was significantly reduced, and the macroscopic porosity \(p\) value was rapidly reduced at the early stage of vibration. With the increase in vibration time, the large bubbles became exhausted, and the small pore-size bubbles were predominantly discharged. However, the tiny bubbles rose to the surface slowly, and the macroporosity \(p\) value changes in the late vibration period were slight. Analysis showed that the macroporosity should be <0.3%.  
(4) According to the influence of the vibrating parameters on the performance of slipform concrete, the equations for the optimal vibrating parameters and paving speed of slipform concrete were derived by combining the actual paving construction requirements. When slipform paving large thickness (\(\geq\)42 cm) concrete, the range of the optimal vibration coefficient \(K\) value was 1.6-2.0, and the optimal vibration parameter equation is:  
\[T=\left\{\begin{array}{l}Kt\\ K\frac{H\eta}{4696.482(\rho_{C}-0.0858)}\end{array}\right.\]  
The paving speed equation is given by:  
\[V=\left\{\begin{array}{l}\frac{60L}{Kt\cos\theta}\\ \frac{4696.482(\rho_{C}-0.0858)}{KH\eta\textless\cos\theta}\end{array}\right.\]  
(5) The airport road surface slipform paving field test showed that the engineering practice paving effect and indoor tests were similar. The slipform concrete vibration construction performance and the paving forming overall effect were good, indicating that slipform concrete ratio parameters and admixtures are significant. The overall compactness of concrete after hardening was high, and the SC value of the segregation rate was <0.15, indicating that the equations of the best vibration parameters and paving speed of slipform construction were feasible. These factors can significantly control the construction process of paving large-thickness concrete in slipform.  
Conceptualization, C.H. and M.C. ([PERSON]); methodology, C.H.; software, M.C. ([PERSON]); investigation, M.C. ([PERSON]); resources, C.H.; data curation, M.C. ([PERSON]) and M.C. ([PERSON]); writing--original draft preparation, M.C. ([PERSON]); writing--review and editing, M.C. ([PERSON]); supervision, C.H.; project administration, C.H.; funding acquisition, C.H. All authors have read and agreed to the published version of the manuscript.  
This research is financially supported by the National Natural Science Foundation of China (Grant No. 51978172).  
**Institutional Review Board Statement:** Not applicable.  
Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.