Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Warsaw University of Technology Faculty of Civil Engineering, Mechanics and Petrochemistry www.pw.plock.pl Influence of specimen size on results of concrete sorptivity measurements Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak

Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Concrete sorptivity Sorptivity In 1957 John Philip introduced the term sorptivity and defined it as a measure of the capacity of the medium to absorb or desorb liquid by capillarity. According to Christopher Hall and William Hoff, the sorptivity expresses the tendency of a material to absorb and transmit water and other liquids by capillarity. The sorptivity is widely used in characterizing soils and porous construction materials such as brick, stone and concrete. Influence of specimen size on results of concrete sorptivity measurements Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Warsaw University of Technology Faculty of Civil Engineering, Mechanics and Petrochemistry

Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Sorptivity is associated with the majority of destruction processes taking place in plain and reinforced concrete. The penetration of the harmful substances can take place with different intensity. Influence of specimen size on results of concrete sorptivity measurements Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Warsaw University of Technology Faculty of Civil Engineering, Mechanics and Petrochemistry

Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Mass method – unidirectional flow 0.5 t S m s * = 0.5 a t S s m + * = Sorptivity test methods can be generally divided into two groups: mass methods, in which the amount of water that penetrated the concrete is determined, based on specimen weight changes. Influence of specimen size on results of concrete sorptivity measurements Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Warsaw University of Technology Faculty of Civil Engineering, Mechanics and Petrochemistry

Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Volumetric method – multidirectional flow t c S s m * + = 0.5 / t c S s m * + = 0.5 0.5 on specimens and the volumetric methods, in which we measure the volume of water penetrating through the defined surface. on structure Influence of specimen size on results of concrete sorptivity measurements Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Warsaw University of Technology Faculty of Civil Engineering, Mechanics and Petrochemistry

Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Covercrete Absorption Test (CAT) PN-EN 13057:2004 Figg’s method PN-EN 13580:2004 ASTM C1585 - 13 PN-EN 480-5:2008 Hall’s mass method PN-EN 1015-18:2003 DeSouza Apparatus PN-EN 772-11:2011 SAABS SANS 516-3 Test method T362 BS 1881-122:2011 However, this general division does not reflect the richness of the testing procedures and standards. They differ substantially from each other not only in specimens preparation but even in specimen size. NT BUILD 368 POROSItester Test ISAT BS 1881-208:1996 Autoclam Permeability System PN-EN ISO 15148:2004 Influence of specimen size on results of concrete sorptivity measurements Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Warsaw University of Technology Faculty of Civil Engineering, Mechanics and Petrochemistry

Specimens sizes for popular test methods Typical sizes for popular Hall’s mass method Area difference about 80 x Durability Index The figure shows a comparison of the specimen size and water entry area for the various methods. The differences are very large. AutoClam POROSItester Influence of specimen size on results of concrete sorptivity measurements Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Warsaw University of Technology Faculty of Civil Engineering, Mechanics and Petrochemistry

Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Dias in the quite often cited paper expressed the opinion, that the specimen size has no effect on the result. However, he investigated only the cylindrical specimens of different thickness with the same area of water entry. The 15148 standard allows different specimen sizes assuming no need to revise the results depending on the size. Influence of specimen size on results of concrete sorptivity measurements Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Warsaw University of Technology Faculty of Civil Engineering, Mechanics and Petrochemistry

Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Hall draws attention to the size of the specimen but does not provide specific data regarding the minimum size or conversion factors. Influence of specimen size on results of concrete sorptivity measurements Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Warsaw University of Technology Faculty of Civil Engineering, Mechanics and Petrochemistry

Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Testing stands mass and volumetric method The article presents research performed with use of both metods on specimens with diameters from 30 mm to 120 mm and additionally by mass method on cubic specimens which equivalent diameter was 112.7 mm and 169.3 mm. The specimens before the test was oven-dried to a constant mass at 105°C. The test was carried out in a laboratory at relative humidity 50% and temperature 20°C Influence of specimen size on results of concrete sorptivity measurements Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Warsaw University of Technology Faculty of Civil Engineering, Mechanics and Petrochemistry

Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Three concrete mixtures were prepared with w/c ratio from 0.40 to 0.83. Mix proportions and basic characteristics are summarized in the table. Influence of specimen size on results of concrete sorptivity measurements Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Warsaw University of Technology Faculty of Civil Engineering, Mechanics and Petrochemistry

Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Plots of the result of the sorptivity depending on water entry diameter were done for both methods. Functional dependencies were matched ... Influence of specimen size on results of concrete sorptivity measurements Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Warsaw University of Technology Faculty of Civil Engineering, Mechanics and Petrochemistry

Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak For each matching function confidence intervals were drawn, as well as for the result obtained by the mass method on specimen of 225 cm2 entry area. The result was marked as S15 Influence of specimen size on results of concrete sorptivity measurements Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Warsaw University of Technology Faculty of Civil Engineering, Mechanics and Petrochemistry

Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Results of both methods, for each concrete, are approaching the asymptote. Influence of specimen size on results of concrete sorptivity measurements Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Warsaw University of Technology Faculty of Civil Engineering, Mechanics and Petrochemistry

Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak For specimen diameter greater than 100 mm results lie within the cofidence interval of S15 value. Influence of specimen size on results of concrete sorptivity measurements Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Warsaw University of Technology Faculty of Civil Engineering, Mechanics and Petrochemistry

Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Taking into account the previously presented results we suggest the use of specimens with a minimum diameter of 100 mm. If you use smaller specimens, it is recommended to use the conversion factors presented in the table (to recalculate obtained results). Research on the impact of scale effect on sorptivity measurement results should be continued and expanded. Values of the conversion factors from the table should be confirmed or, if it will be necessary, corrected. Omitting the influence of water ingress area on sorptivity test result is simplistic too far. Influence of specimen size on results of concrete sorptivity measurements Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Warsaw University of Technology Faculty of Civil Engineering, Mechanics and Petrochemistry

Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Thank you for your kind attention Influence of specimen size on results of concrete sorptivity measurements Wojciech Kubissa, Roman Jaskulski, Krzysztof Pietrzak Warsaw University of Technology Faculty of Civil Engineering, Mechanics and Petrochemistry