Use of polypropylene fibres to increase the resistance of reinforcement to chloride corrosion in concretes

Abstract

Concrete with the addition of polypropylene fibres is more cohesive and has better adhesion, deformability and tightness because the fibres “bind” the concrete matrix together and prevent large pores from forming in the concrete mix and limit the formation and spread of shrinkage cracks. Therefore, it can be assumed that polypropylene fibres affect the effectiveness of the concrete cover as a layer protecting steel bars against corrosion. This article presents the results of tests allowing us to estimate the effect of addition of polypropylene fibres on the reduction of reinforcing bars corrosion in concrete caused by the action of chlorides. Evaluation of the degree of corrosion of the reinforcement was analysed using the electrochemical polarisation galvanostatic pulse technique. The use of such a method allowed for the quantitative estimation of the effect of the addition of polypropylene fibre on the reduction of corrosion activity of the reinforcement in concrete.

Evaluating the Impact of Concrete Design on the Effectiveness of the Electrochemical Chloride Extraction Process

“…Another week of extraction did not bring such spectacular changes in corrosion current intensity in the specimens tested, particularly in concrete C2. Although final values of corrosion potential in concrete C1(C1.1(E corr = 540 mV); C1.2(E corr = 752 mV) and C2 (C2.1(E corr = 332 mV); C2.2(E corr = 580 mV) generally showed a downward trend, when compared to maximum values measured for C1.1 (an increase by 0.1%) C1.2 (a drop by 22%), C2 (a drop by 22%); C2.2 (a drop by 40%) the majority of these results did not reach the value taken for passivated steel according to [ 29 , 30 ].…”

“…On the other hand, values of the measured corrosion current ranged from the reference value measured prior to migration µA) to the maximum value obtained prior to extraction µA). Based on the paper [ 29 ], reference values of corrosion current in the specimens C1 could be regarded as the values which signalled the unexpected corrosion, and the maximum values could indicate high corrosion activity.…”

“…Figure 6 b shows a comparison of results from six measurements of corrosion potential E corr of the steel reinforcement in concrete from two chosen test elements made of tested concretes. Taking into account the assumptions described in the papers [ 29 , 30 ], the first reference measurement taken prior to migration indicated that both corrosion potential (E corr ( < 350 mV) and corrosion current intensity (i corr < 0.3 µA) suggested the passive state of all test elements. Another measurement taken after 7 days of chloride ions migration under the accelerated action of the electric field and 3 days after switching off the system indicated the onset of corrosion in all four specimens on the basis of corrosion potential values and intensity of corrosion current.…”

Influence of Steel Fibers Content on Selected Mechanical Properties - Experimental Tests

“…As a material that independently transfers tensile stresses, it is not a perfect material and research is still ongoing to improve the properties of concrete. Concrete parameters can be improved by applying fiber reinforcement evenly distributed in the concrete mix [27][28][29].…”

Electrochemical Corrosion in Bars of AISI 304 Embedded in Concrete Immersed in Marine-Sulfated Environment

“…However, if at first it was thought that reinforced concrete had unlimited durability, over time it was determined that one of the main causes of premature damage in civil works built with reinforced concrete was the corrosion of reinforcing steel, causing expenses for billions of dollars in the world [5]- [9], in 1986, it was estimated that more than 244,000 bridges in the USA had significant deterioration, the main cause being corrosion of the reinforcing bars of concrete structures [10]- [12].…”