Issue 44

B. Rahmanzadeh et alii, Frattura ed Integrità Strutturale, 44 (2018) 16-24; DOI: 10.3221/IGF-ESIS.44.02 20 H YDRAULIC CONDUCTIVITY COEFFICIENT he hydraulic conductivity of the concrete was tested using by Penetration Method according to ASTM-C1920-5 (Eq. 1). Concrete hydraulic conductivity coefficient =   p H V Th 2 / 2 (1) where H p : Water penetration depth [m], T : Influence time [s], h : Pressure height [m], V : Concrete porosity. Fig. 4 illustrates the machine used for performing the hydraulic conductivity of the concrete tests. Fig. 5 shows the water permeability depth in terms of various amounts of water-cement ratio. The mentioned data showed that increasing the water-cement ratio, increases water permeability depth. Figure 4: Hydraulic conductivity of the concrete test machine 0.5 1 1.5 2 2.5 3 3.5 0.3 0.35 0.4 0.45 0.5 Water permeability depth (mm) W/C Figure 5 : Water permeability depth in terms of different values of water-cement ratio It is noteworthy that the following formula is used for calculating the permeability coefficient of concrete.       p p K h t h 2 / 2 (2) where: K p is permeability coefficient of concrete [m/s]; h p is water permeability depth [m]; t is water permeability time [s]; h is height arising from pressure [m] and v is porosity of concrete. The following equation is used for porosity calculation: T