The blazar 3C~454.3 is known for its strong outburst across the whole electromagnetic spectrum. Multi-wavelength radio observations enable us to study the spectral variability of relativistic radio jets in the source. In this work, we use multi-wavelength radio observations at 3~GHz to 340~GHz. From the spectral analysis using the multi-wavelength data, we found two synchrotron self-absorption~(SSA) features in the source spectra for compact variable emission regions. One peak of the SSA spectral features is found at a frequency range of 3--37~GHz~(LSS), and the other at 55--125~GHz~(HSS). By using the derived SSA turnover frequency and peak flux density, we estimated B-field strength ($B_{\rm SSA}$) for the SSA regions in the relativistic jets. The estimated B-field strengths of the HSS and the LSS features are $\gtrsim0.1~{\rm mG}$ and $>3~{\rm mG}$, respectively. The LSS B-field strength is comparable at the first epoch, and even stronger than the estimated B-field strength~($B_{\rm EQ}=2\sim5~{\rm mG}$) under the equipartition condition in the other epochs before the 2014 June $\gamma$-ray flare, implying a magnetic dominance in this region. We found the LSS region is related to the quasi-stationary component~(C) $\sim0.6~{\rm mas}$ away from the VLBI core at 43~GHz. And we found that component C is considered as a recollimation shock based on the analysis of the jet width and polarimetric characteristics.