Relationship Among the Permeation Rate of Water into Concrete, the Mix Design, Curing, and the Degree of Drying

Abstract

Water permeation into concrete causes various types of deterioration in concrete structures such as rebar corrosion, frost damage, ASR, etc.; however, the evaluation of the water permeation rate is difficult. This paper proposes a simple equation to evaluate the water permeation rate into concrete, based on basic information such as the mix design, curing condition, and degree of drying. Concrete specimens are cast, cut into slices of different thicknesses, and the time taken for water penetration is measured. The permeation rate is calculated from the relationship between the obtained permeation time and the slice thickness. Additionally, a literature survey is conducted to collect the water permeation rate in various types of concrete. A prediction equation for the water permeation rate is proposed, based on the data. Although this data contains various types of concrete with/without the admixture material, different water-to-binder ratios, and different curing conditions, all the calculated values fall within a range of ±150% of the data from literature.

Durability Design Method Considering Reinforcement Corrosion due to Water Penetration

“…The comparison between A calculated using Eq. (13) and that calculated from the data in the literature (Koshikawa and Ogihara 1991;Sakai and Kishi 2016;Sakai et al 2017;Suzuki and Ueda 2015;Tsuchiya et al 2008;Ueda and Suzuki 2016a;Zhang et al 2011) is shown in Fig. 4.…”

“…4. The test conditions used in these studies are summarized in Sakai et al (2017). Thus far, the number of studies in literature that have reported the rate of increase of the water penetration depth with time is limited; to the best of the authors' knowledge, the data reported here constitute all the literature that the authors could find.…”

“…The value of β 1 was set to one for water curing, two for sealed or high humidity curing, and three for curing in the air. The details regarding the curing conditions and β 1 are listed in the literature by Sakai et al (2017). In the figure, most of the data can be noted to be within the range of ±150% of the A calculated using Eq.…”

“…Based on the data of experiments that involved the measurement of the water penetration with time, the water penetration rate was calculated using Eq. (13) (Sakai et al 2017).…”

“…Figure 10 shows the effect of β on the cover thickness. It has been indicated that setting β to 0.2 for concrete cured under water, to 0.7 for concrete that is seal cured or cured in high humidity, and to 1.5 for concrete exposed to the air 24 h after casting leads to a satisfactory prediction of the water penetration rate (Sakai et al 2017). Applying these values in the design, as shown in the figure, the value of β of 1.5, 0.7 and 0.2 lead to a cover thickness of 53 mm, 30 mm, and 14 mm, respectively, when W/B is 0.55.…”