Corrosion behavior and optimization of air‐entrained reinforced concrete, incorporating microsilica

Abstract

Nowadays, corrosion evaluation of steel embedded in reinforced concrete (RC) plays an important role in repair, protection and maintenance of RC structures. Air‐entraining agent (AEA) and microsilica (MS) are among the most important admixtures, which affect the corrosion rate (CR) of RC. Specifically, 12 mix designs incorporating different contents of AEA (ie, 0, 0.7, 1.4, 2.1, 2.9, and 3.6% by weight), half with 10% MS, were constructed. The corrosion behavior of RC specimens after exposure to 3.5% NaCl environment was investigated using half‐cell potential (HCP) and electrical resistance (ER) as conventional tests and Tafel polarization as a more powerful corrosion test. Moreover, an optimization process was conducted on the mix design parameters using Taguchi and Factorial methods to analyze the effective factors and sensitivity of CR to each factor. The results of Tafel test indicate that they are noticeably more reliable and reasonable as compared to HCP and ER tests. Moreover, the results show that incorporating a low content of AEA (up to 0.7%) effectively improves the corrosion behavior of RC specimens, while the mix design containing 0.7% AEA together with 10% MS is the optimal design in terms of a decreased CR. The results also show that Factorial is a more applicable method in the field of corrosion evaluation of RC, due to the yield of more accurate findings as compared to Taguchi.

The Study of Cement Concrete with Improved Properties Based on the Use of Astivated Silica Fume

“…Authors concluded that 6% of microsilica and 1,5% of nanosilica improves strength characteristics, electric impedance and reduces capillary intake. Results of our research actually coincide with research of other scientists [2][3][4][7][8][9]. Reducing of concrete consumption by its substitution by microsilica, has a positive influence to physico-chemical characteristics of concrete.…”

“…The theoretical basis received of work becameof group the research of national isand foreign scientists is was setdevoted to structuremarkcement compositionChernishovaand problems of modification of uniquehydrational systemssolidification with the use of ismineral and chemicalprocessadditives. Based on works of Ailer R., Kaprielov S.S. [1,2] corresponding performance of amorphous quartz in water, acid and alkaline environment, and in the view of information corresponding cement modification, where the complex additives containing particles of SiO2 similar in crystallochemical structure are preferable, it could be considered that chemical activation of microsilica is cheap and upcoming trend for modification of structure of cement rock and cement on its basis. Analysis of literary sources indicated that one of effective pozzolanic active mineral additive for cement matrix and cement on its basis, is microsilica -powdery waste of ferroalloy industry containinf SiO2 not less than 91% [5,6].…”

Strength Properties of Nano and Micro Silica Mortar

“…The cementitious content of all mixes is maintained constant using a constant dose of 2.5% high range water reducer (superplasticizer) by weight of cementitious materials along with a fixed 0.4 water/cementitious ratio. Mechanical properties of cement mortars are dependent on many parameter, and according to the previous literature properties are influenced by the water/cement ratio (W/C) [21], aggregate/cement ratio (A/C) [22,23], age [24,3], and admixture dose [25,26]. Tension specimens include T in their ID.…”