Characterization of mortar samples using ultrasonic scattering attenuation

AbstractIn this paper, volume fraction and size of aggregates in highly dispersive materials have been estimated using ultrasonic techniques. Estimations were made by obtaining the best fit between experimental scattering attenuation and theoretical predictions obtained from an N-phase extension of the dynamic generalized self-consistent method (DGSCM) proposed by Yang [J. Appl. Mech. 70 (2003) 575]. Furthermore, a time-frequency procedure has been designed to estimate frequency-dependent scattering attenuation from experimental measures. The research was conducted with several cement mortar specimens made by taking into account different aggregate-to-cement ratio and water-to-cement ratio. Estimations of both size and volume fraction, were made and good agreements was found between experimental attenuation curves and theoretical predictions

C10H18N2Na2O10 inhibition and adsorption mechanism on concrete steel-reinforcement corrosion in corrosive environments

C10H18N2Na2O10 (ethylenediaminetetra-acetic acid disodium salt) inhibition and adsorption mechanism on the corrosion of steel-reinforcement corrosion in concrete immersed in corrosive environments were investigated in this paper. For this, seven different concentrations ranging from 0% to 0.667% C10H18N2Na2O10 per weight of cement were admixed in steel-reinforced concretes immersed in saline and in acidic sulphate test-media and these were monitored using electrochemical techniques. Statistical analyses of the scatter of measured data from these, as per ASTM G16-95 R04, showed that C10H18N2Na2O10 > 0% admixtures portrayed excellent efficiency at inhibiting steel-reinforcement corrosion in the saline environment. However, attaining comparably high inhibition of steel-reinforcement corrosion in concrete immersed in the acidic sulphate environment exhibited greater dependency on high C10H18N2Na2O10 admixture concentration in the steel-reinforced concretes. Different models of adsorption isotherms bear indications of chemical adsorption, chemisorptions, as the prevalent adsorption mechanism of C10H18N2Na2O10 on steel-reinforcement in both of the corrosive environments