Ponding Test Research Articles

Effect of Mineral Admixtures and Water/Binder Ratios on the Resistance to the Chloride Ions Penetration into Concrete

In this study, concrete prisms were made with three mineral admixtures: fly ash, blast furnace slag or silica fume and with three water-to-binder ratios(w/b). Chloride penetration was measured by the rapid chloride permeability test (RCPT)-ASTM C1202, 150-days ponding test and alternate wetting and drying test by cyclic loading with salt solution and oven drying, and the results by the three test methods were compared. This paper discussed the effects of mineral admixtures and w/b on the concrete chloride permeability. Blending concrete with blast furnace slag, fly ash or silica fume was beneficial with regard to the resistance against chloride ion penetration. Concrete specimens with lower w/b showed lower chloride permeability.

Water absorption, permeability, and resistance to chloride-ion penetration of lightweight aggregate concrete

This paper presents an experimental study to evaluate effect of cumulative lightweight aggregate (LWA) content (including lightweight sand) in concrete [water/cement ratio ( w/ c) = 0.38] on its water absorption, water permeability, and resistance to chloride-ion penetration. Rapid chloride penetrability test (ASTM C 1202), rapid migration test (NT Build 492), and salt ponding test (AASHTO T 259) were conducted to evaluate the concrete resistance to chloride-ion penetration. The results were compared with those of a cement paste and a control normal weight aggregate concrete (NWAC) with the same w/ c and a NWAC (w/ c = 0.54) with 28-day compressive strength similar to some of the lightweight aggregate concrete (LWAC). Results indicate that although the total charge passed, migration coefficient, and diffusion coefficient of the LWAC were not significantly different from those of NWAC with the same w/ c of 0.38, resistance of the LWAC to chloride penetration decreased with increase in the cumulative LWA content in the concretes. The water penetration depth under pressure and water sorptivity showed, in general, similar trends. The LWAC with only coarse LWA had similar water sorptivity, water permeability coefficient, and resistance to chloride-ion penetration compared to NWAC with similar w/ c. The LWAC had lower water sorptivity, water permeability and higher resistance to chloride-ion penetration than the NWAC with similar 28-day strength but higher w/ c. Both the NWAC and LWAC had lower sorptivity and higher resistance to chloride-ion penetration than the cement paste with similar w/ c.

Modified Inverted Cup Test Method for Evaluating Moisture Penetration through Construction Materials

Abstract This paper presents a state-of–the-art review of the modified inverted cup (MIC) test method. The inverted cup method was introduced into ASTM E96, “Standard Test Method for Water Vapor Transmission of Materials,” several decades ago. However, its capability in evaluating moisture response of building materials has not been fully realized. Recently, a consensus was reached to develop an independent MIC standard under the jurisdiction of the same ASTM committee. The MIC test method quantifies moisture transport in liquid and vapor phases together and has several advantages over its counterpart ASTM D779, “Standard Test Method for Water Resistance of Paper, Paperboard, and Other Sheet Materials by the Dry Indicator Method,” boat test method. The MIC test method can also be employed in evaluating effectiveness of surface treatments including hydrophobic sealers and coatings on material surfaces as well as water resistive barriers, water vapor retarders, and certain insulation products. This paper also discusses the differences between various moisture transport tests, including ASTM E96 water vapor transmission, D779 (boat test method), and ponding test to resolve confusion related to their use. The paper shows that the results of MIC tests are valuable in quantifying moisture response of different materials.

Durability of lightweight OPS concrete under different curing conditions

The use of waste materials and by products from different industries for building construction has been gaining increased attention due to the rapid depletion of natural resources. It has been found that oil palm shell (OPS), which is a waste from the agricultural sector, can be used as coarse aggregate for the manufacture of structural lightweight concrete. However, for OPS concrete to be used in practical applications, its durability needs to be investigated. Therefore, this paper presents the durability performance of OPS concrete under four curing regimes. The durability properties investigated include the volume of permeable voids (VPVs), sorptivity, water permeability, chloride diffusion coefficient and time to corrosion initiation from the 90-day salt ponding test, and Rapid Chloride Penetrability Test (RCPT). Results showed that the durability properties of OPS concrete were comparable to that of other conventional lightweight concretes and proper curing is essential for OPS concrete to achieve better durability especially at the later ages.

Chloride Ion Transport in Bridge Deck Concrete under Different Curing Durations

During freezing temperatures, ice accumulates on exposed concrete slabs such as bridge decks. Deicing salts such as calcium chloride are applied to control this ice formation. These salts migrate down to the reinforcing steel, and they can break down the passivation layer on steel, causing it to corrode. This paper is part of a broader research study to explore the possibility of opening the bridge decks earlier than the 10–12 days as practiced now, by decreasing the number of wet-mat curing days. Seven concrete mixtures typically used in Texas bridge decks were evaluated for chloride permeability using the ponding test (AASHTO T259). The primary experimental variables were the curing duration, type and percentage of supplemental cementitious materials, type of coarse aggregate, duration of ponding, and the surface preparation of ponded concrete specimens. Results of the investigation indicated that curing duration may be decreased for some concrete mixtures as no apparent improvement was shown after a specific curing duration, which ranged from 2 to 8 days depending on the mix.

Influence of transverse crack width on reinforcement corrosion initiation and propagation in mortar beams

This paper discusses the relationship between crack widths, chloride diffusivity, and corrosion rate of cracked mortar beams. Flexural loads are introduced to generate crack widths ranging from 29 to 390 µm. The specimens were subjected to accelerated corrosion by immersion in a 5% NaCl solution and a constant voltage of 12 V. In addition, salt ponding tests were conducted to determine the chloride ion transport properties. The results showed that as the crack width increased, the effective diffusion coefficient (corrosion initiation) and mass loss of steel reinforcing bars due to the accelerated corrosion (corrosion propagation) also increased. For crack widths less than about 135 µm, the effect of crack width on the effective diffusion coefficient and mass loss of steel reinforcing bars embedded in mortar specimens was found to be marginal when compared with the virgin specimens. Therefore, it was concluded that the effect of crack width on the corrosion initiation and propagation period was more pronounced when the crack width is greater than about 135 µm. Moreover, a significant amount of self-healing was observed for the cracks that have widths below 50 µm when subjected to the NaCl solution exposure.

Determination of diffusion coefficient of chloride in concrete: an electrochemical impedance spectroscopic approach

For predicting the service life of concrete structures in marine environment, diffusion of chloride (D) is an important parameter. Electro-migration tests and ponding tests are two techniques conventionally adopted, however they are destructive in nature. EIS (Electrochemical impedance spectroscopy) being non-destructive appears a promising technique to arrive at ‘DR’ (D from EIS) in situ in structures. The DR of ordinary Portland cement concrete (OPC) was compared with that of Portland pozzolana cement concrete (PPC). The effect of curing on DR was analyzed. The splash zone condition was created by subjecting the specimens to alternate wetting and drying cycles. At the end of 28 days of curing, the DR of PPC concrete is only 66.7% of that obtained in OPC concrete. A linear correlation was established between DR and the porosity of the concrete. Due to pozzolanic reaction, the rate of pore refinement is faster in PPC concrete compared to OPC concrete. In M25-PPC concrete at the end of 28 days of curing, the pore size is decreased to 14.6% of that obtained at the end of 3 days of curing. The reduction of pore size by densification of pore structure due to pozzolanic reaction reduces the DR value in PPC concrete. In 30 MPa concrete the DR under wet cycle is 3 times higher than in dry cycle, which implied that corrosion is initiated 3 times faster in concrete exposed to the splash zone condition.

Relation between the diffusion characteristic of concrete from salt ponding test and accelerated chloride migration test

In order to understand the relationship between the diffusion coefficient obtained from 90-day salt ponding test and the migration coefficient obtained from accelerated chloride migration test (ACMT; the electrochemical technique is applied to accelerate chloride ion migration), the transport properties of concrete obtained from those two methods are compared. The chloride profile was measured after ponding test, and the diffusion coefficient was calculated from the Fick's second law. The transport properties were calculated from the modified Fick's second law based on measurements of the penetration depth from colourimetric method after ponding test and ACMT. The experimental result shows that the diffusion coefficients obtained from ponding test correspond well with the migration coefficients. In ponding test, the diffusion coefficient obtained from the profile method and colourimetric method is linearly correlated.

Transport Properties of Engineered Cementitious Composites under Chloride Exposure

This paper presents the results of an experimental investigation on the chloride transport properties of engineered cementitious composites (ECC) under combined mechanical and environmental loads. ECC is a newly developed, high-performance, fiber-reinforced cementitious composite with substantial benefit in both high ductility and improved durability due to tight crack width. By employing micromechanics-based material design, maximum ductility in excess of 3% under uniaxial tensile loading can be attained with only 2% fiber content by volume, and the typical single crack fracture behavior commonly observed in normal concrete or mortar is converted to multiple microcracking in ECC. In this study, immersion and salt ponding tests were conducted to determine chloride ion transport properties. Under high imposed bending deformation, the preloaded ECC beam specimens reveal microcracks less than 50 μm and an effective diffusion coefficient significantly lower than that of the similarly preloaded reinforced mortar beam because of the tight crack width control in ECC. In contrast, cracks larger than 150 μm are easily produced under the same imposed deformation and have significant effects on effective diffusion coefficient of reinforced mortar. Moreover, through the formation of microcracks, a significant amount of self-healing was observed within the ECC cracks subjected to NaCl solution exposure.

The chloride ponding test and its correlation to the accelerated chloride migration test for concrete

In this study, the total chloride content and penetration depth of concretes were measured by the 90‐day salt ponding test, and the flux of chloride ions passing through the concrete was measured by the accelerated chloride migration test (ACMT; the electrochemical technique is applied to accelerate chloride ion migration). Fick's second law was fitted to the data from the ponding test to determine the diffusion coefficient. The steady‐state and the non‐steady‐state migration coefficients were determined from the modified Fick's first and second laws, respectively. The steady‐state migration coefficient, the non‐steady‐state migration coefficient, and the diffusion coefficient were compared. The non‐steady‐state migration coefficient, steady‐state migration coefficient, and diffusion coefficient were linearly correlated. The non‐steady‐state migration coefficient gave the highest value, being about 1.5 times higher than the steady‐state migration coefficient, and up to about 4 times higher than the diffusion coefficient. Since the 90‐day ponding test is time‐consuming, the ACMT provides a time saving method to obtain the transport property of concrete.

Chloride ion penetration in bridge deck concrete

During freezing temperatures, ice accumulates on exposed concrete slabs such as bridge decks. De-icing salts such as calcium chloride are applied to control this ice formation. These salts migrate down to the reinforcing steel and they can break down the passivation layer on steel, causing it to corrode. This paper is part of a broader research study, sponsored by the Texas Department of Transportation, to explore the possibility of opening the bridge decks to full traffic following construction/repair earlier than the 10 to 12 days as practised now in Texas. Seven concrete mixtures typically used in Texas bridge decks were evaluated for chloride permeability using the ponding test. The primary experimental variables were the curing duration, type and percentage of supplemental cementitious materials, type of coarse aggregate, duration of ponding, and the surface preparation of ponded concrete specimens. The results of this investigation indicated that chloride permeability decreased with increasing curing duration for the top 1 in (2·5 cm) layer of concrete. It was also observed that curing duration may be decreased for some concrete mixtures, as no apparent improvement was shown after a specific curing duration, which ranged from 2 to 8 days depending on the mix. In addition, increasing the amount of cementitious materials such as fly ash from 20% to 30% considerably reduced the chloride permeability.

The relationship between pore structure and chloride diffusivity from ponding test in cement-based materials

In this study, the total chloride contents at different penetration depth were measured after the 90-day ponding test, and the Fick's second law of diffusion was fitted to the data to determine the diffusion coefficient of concrete. The porosity and the continuous pore diameter of the same mortar in concrete were examined with the mercury intrusion porosimetry (MIP) method. The continuous pore diameter was used to assess the connectivity of cement-based materials. The diffusion coefficients obtained from ponding test were compared and correlated with the capillary porosity (pore diameter between 30 and 10000 nm) and the continuous pore diameter from the MIP testing. A good correlation between the capillary porosity and the diffusion coefficient of concrete has been determined. The continuous pore diameter is linearly related to the diffusion coefficient of concrete.

A comparison of transport properties for concrete using the ponding test and the accelerated chloride migration test

In order to develop a better understanding of the relationship between 90-day salt ponding test and accelerated chloride migration test (ACMT; the electrochemical technique is applied to accelerate chloride ion migration), the transport properties for concrete obtained from ACMT are compared to the diffusion coefficient from ponding test. The plain cement concrete, fly ash concrete, and slag concrete with different w/b ratios (0.35, 0.45, 0.55, and 0.65) were used. In this study, the total chloride content and penetration depth of concretes were measured after the ponding test, and the Fick's second law of diffusion was fitted to the data from experiment to determine the diffusion coefficient. The non-steady-state diffusion coefficient, the migration coefficient, and the current corresponding to the 30000 coulomb, charge passed obtained from ACMT in the previous works were compared with the diffusion coefficients obtained from ponding test. Parallel tests show that the diffusion coefficients obtained from ponding test correspond well with the non-steady-state diffusion coefficient, the migration coefficient, and the current corresponding to the 30000 coulomb charge passed obtained from ACMT, although the diffusion coefficient measured by ponding test is different from that measured by the ACMT in non-steady state and steady state.

A comparison of transport properties for concrete using the ponding test and the accelerated chloride migration test

A comparison of transport properties for concrete using the ponding test and the accelerated chloride migration test

The diffusion characteristic of concrete with mineral admixtures between salt ponding test and accelerated chloride migration test

In order to develop a better understanding of the relationship between 90-day salt ponding test and accelerated chloride migration test (ACMT; the electrochemical technique is applied to accelerate chloride ion migration) to assess the resistance of concrete to chloride penetration. The plain cement concrete and concrete containing different type of mineral admixtures (fly ash and slag) with w/ b ratios of 0.35, 0.45, 0.55 and 0.65 were used. In this study, the total chloride content and penetration depth of concretes were measured after the ponding test, and the Fick’s second law of diffusion was fitted to the data from experiment to determine the diffusion coefficient. The non-steady-state diffusion coefficient was calculated from the modified second Fick’s law by using ACMT in the previous study. The chloride diffusion coefficient from ponding test and the non-steady-state diffusion coefficient from ACMT were compared. The results for all mixtures show that the chloride diffusion coefficient from ponding test and the non-steady-state diffusion coefficient from ACMT are linearly correlated.

Comparative evaluation of canal seepage investigation techniques

Various methods are used to estimate the canal seepage rate such as empirical formulae, analytical or analogue studies and the direct seepage measurement techniques, i.e. seepage meters, ponding tests and inflow–outflow tests. Considering significance of physical measurement techniques both ponding and inflow–outflow methods were used to evaluate the seepage losses. These methods have their merits, demerits and limitations which are well understood. However, while interpreting seepage loss evaluations, there can be independent random errors, like the fluctuations in flow conditions affecting different current meter positions, and systematic errors, like the use of different instruments or different methods to measure different terms in the balance. These errors have to be distinguished. The data from various studies in the region have been reviewed and analyzed. A statistical analysis of a number of replications of ponding and inflow–outflow test data of the seepage estimation work on various canals under the Fordwah Eastern Sadiqia (South) project, Bahawalnagar, Pakistan has been done to show the accuracy of results achieved through both the methods. It has been shown that the ponding method is more accurate than the inflow–outflow method as variability of various statistical parameters from the ponding tests is comparatively less. It is proved that inflow–outflow tests should not be used for seepage investigations where seepage rates are fairly small and there is no possibility to use sufficiently long reaches.

Chloride Penetration in Nonsaturated Concrete

The two governing equations that describe the diffusion of chloride ions into nonsaturated concrete are established. Material models for the four material parameters involved in the governing equations are developed, including chloride binding capacity, chloride diffusion coefficient, moisture capacity, and moisture diffusion coefficient. The planned attempt is to establish material models based on analytical results first, and if this is not possible, to develop empirical models based on dominant physical or chemical mechanism(s) at different scale levels and calibrate the individual model by related test data. The alternating-direction implicit (ADI) finite-difference method was employed for solving coupled two-dimensional moisture diffusion and chloride penetration equations. The numerical solutions are compared with the experimental results obtained by the 90-day ponding test (AASHTO T259-80). The numerical prediction agrees very well with the test data. Free chloride concentration profiles at different depths and different ages of concrete slab are presented. Two limiting cases for different initial relative humidity levels are analyzed in detail to study the dependence of the chloride diffusion on the moisture diffusion in nonsaturated concrete.

電気泳動試験による高強度フライアッシュ人工骨材（ＨＦＡ骨材）コンクリートの塩分浸透評価

Chloride ingress into concrete with high strength lightweight aggregate made of fly ash (HFA aggregate) as the coarse aggregate was evaluated by a steady state migration test and chloride ponding test. It was found that the migration coefficient obtained from the migration test could represent appropriate ranking on chloride ingress into the concrete with different W/Cs. The effect of HFA aggregate on the chloride ingress was negligible and a similar migration coefficient to that of normal weight aggregate was given. In addition, an observation using EPMA showed no chloride ion present in the HFA aggregate itself after the migration test. Chloride ponding test also exhibited same ranking providing increased apparent chloride diffusion coefficients with increased W/C. Migration coefficients might be related quantitatively to the apparent diffusion coefficient with chloride binding isotherm being properly considered.

Water permeability and chloride penetrability of high-strength lightweight aggregate concrete

This paper presents an experimental study on the water permeability and chloride penetrability of high-strength lightweight concrete (LWC) in comparison to that of high-strength normal-weight concrete (NWC) with or without silica fume. The results were also compared with those of the concrete at a normal-strength level of about 30–40 MPa. In order to compare the water permeability and chloride-ion penetrability, LWC and NWC had the same proportion by volume. The only difference between them was the coarse aggregate used. The results indicated that at the strength level of about 30–40 MPa, the water permeability of the LWC was lower than that of the corresponding NWC. However, the water permeability of the high-strength LWC and NWC was of the same order. The resistance of the LWC to the chloride penetration was similar to that of the corresponding NWC both in the normal-strength and high-strength levels. As the compressive strength of the LWC was lower than that of the corresponding NWC, the results indicated that for a given 28-day strength, the LWC would probably have high resistance to water and chloride-ion penetration than the NWC. The results indicated that the resistance to the chloride penetration does not seem to be correlated to the water permeability of the concrete. There appears to be, however, a direct relationship between the rapid chloride penetrability determined by ASTM C1202 and the observed chloride penetration depth determined by the immersion and salt ponding tests.

Re-evaluation of the AASHTO T259 90-day salt ponding test

There is a need to develop a better understanding of the relationship among short-, medium-, and long-term tests to assess the resistance of concrete to chloride penetration. In this contribution, a resistivity-based test is compared to a 90-day salt ponding test. The short-term (6-h) rapid chloride permeability test has been criticized for its lack of a scientific basis and poor correlation to the so-called control ponding test. Comparative testing is presented for several concrete and mortar mixtures, which suggests that if modifications are made to test procedures and methods of analysis then the relationship between the results of the resistivity-based test and the diffusion-based test is improved. The 90-day salt ponding test can be improved by using a depth of penetration approach rather than an integral chloride content and by limiting the transport process to diffusion only. Modification to the rapid chloride test by shortening the test time to 30 min did not improve the correlation to other test methods for the range of concretes studied here.