Comparison BetweenD_critConsidering the Abrupt Variation and Inflexion in the Concrete Mercury Intrusion Porosimetry Curve

Abstract

Mercury intrusion porosimetry (MIP) has been widely used to evaluate the quality of concrete through the pore size distribution parameters. Two of these parameters are the critical pore diameter (D crit ) and the percentage of the most interconnected net of pores compared to the total volume of pores. Some researchers consider D crit as the diameter obtained from the inflexion point of the cumulative mercury intrusion curve while others consider D crit as the diameter obtained from the point of abrupt variation in the same curve. This study aims to analyze two groups of concretes of varying w/c ratios, one cast with pozzolanic cement and another with high initial strength cement, in order to determine which of these diameters feature a better correlation with the quality parameters of the concretes. The concrete quality parameters used for the evaluations were (1) the w/c ratios and (2) chloride diffusion coefficients measured at approximately 90 days. MIP cumulative distributions of the same concretes were also measured at about 90 days, and D crit values were determined (1) from the point of abrupt variation and alternatively, (2) from the inflexion point of each of these plots. It was found that D crit values measured from the point of abrupt variation were useful indicators of the quality of the concrete, but the D crit values based on the inflexion points were not. Hence, it is recommended that D crit and the percentage of the most interconnected volume of pores should be obtained considering the point of abrupt variation of the cumulative curve of pore size distribution.

Influence of curing on pore properties and strength of alkali activated mortars

“…The critical and threshold pore diameters of a concrete matrix influence its durability properties [29,30,33]. Lower values of these parameters represent enhanced durability properties.…”

On the Relation between the Gas-Permeability and the Pore Characteristics of Furan Sand

“…The critical pore diameter affects the permeability of the material. The critical pore diameter has been considered as the point of abrupt variation in the intrusion curves by some authors [ 33 ], while some authors suggest the critical pore diameter is obtained from the inflection point. The inflection point is the highest point in the differential intrusion curve.…”