1. The elastic modulus Encp and compressive strength Hcp of a cement paste are dominated by its capillary porosity p, wh

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1 The Elastic Modulus Encp And Compressive Strength Hcp Of A Cement Paste Are Dominated By Its Capillary Porosity P Wh 1 (501.71 KiB) Viewed 40 times

1. The elastic modulus Encp and compressive strength Hcp of a cement paste are dominated by its capillary porosity p, which is a function of w/c ratio and degree of hydration a: 0.68α Excp == 32GPa(1 – p)' = 32GPa w/C+0.32a HCP = 100MPa(1 – p)' = 100MPa 0.68a w/c+0.32a (a) Calculate the capillary porosity, elastic modulus and compressive strength of the cement paste with w/c = 0.45 and a=0.85. (20%) HCP (b) It is assumed that Eucp = Alo HCP)'". Where Encp is in GPA unit, and in MPa unit. Determine the constants A and n. (20%) OHCP (c) Aggregates with an elastic modulus Ex=90GPa are mixed with the cement paste of w/c=0.4 and a=0.95 to produce concrete. Estimate the upper elastic modulus Eupper and lower elastic modulus Erower of the concrete when the volume fraction of aggregates V.=0.6. (20%) (d) Using a computer software, plot the variations of the upper and lower elastic moduli of the concrete with respect to the volume fraction of aggregates V. when w/c=0.38 and a=0.9. (20%) (e) Determine the volume fraction of aggregate V when the ratio of aggregate Eupper / Elower reaches a maximum. (20%)