افزايش دوام بتن در محيط سولفاتي به كمك باكتري

چكيده انگليسي :

Durability Improvement in Sulfate Environment using Bacterial Concrete Farzaneh Nosouhian f nosouhian@cv iut ac ir September Department of Civil Engineering Isfahan University of Technology Isfahan Iran Degree M Sc Language Persian Supervisors Dr Davood Mostofinejad Prof Email address dmostofi@cc iut ac ir Dr Hasti Hasheminejad Assist Prof Email address hhasheminejad@cc iut ac ir Abstract One of the most important issues about concrete is its durability in harsh environments such as sulfate exposure Sulfate ions trigger the cement paste while concrete exposure to sulfate containing environment gradually deteriorates the paste matrix which causes rapid destruction of concrete structures Lots of studies have been carried out to improve the durability of concrete in sulfate environment and many strategies have been suggested Recently researchers have focused on use of biodeposition in concrete to improve its behavior in harsh environments Since the concrete porosity exacerbates the ions penetration the current experimental study is aimed to investigate the influence of using calsium carbonate producing bacterias on concrete durability improvement in sulfate environment To do so two series of specimens were considered In the first series of specimens two different bacterial strains accompanied with mixing water was used to make bacterial concrete Seven groups of mm cubic concrete specimens were made and exposured to saturated magnesium sulfate solution each group contained cubic spesimens which half of them were submerged in water as control In the second series of specimens Four groups of mm cubic concrete specimens were made and surface treated by bacterial solutions using three different bacterial strains Except the specimens made for measuring the day compressive strength each group contained specimens that half of them were exposured to saturated magnesium sulfate solution and the rest were submerged in water as control specimens To investigate the durability improvement of concrete specimens exposured to sulfate environment mass changes volume changes water absorption and compressive strength were determined Furthermore groups of cylinderical concrete specimens with mm diameter and mm height in the first series of specimens and cylinderical groups with the same dimension were prepared in the second series of specimens to investigate the chloride permeability of bacterial concrete by rapid chloride penetration test RCPT Results of the first series showed that using bacteria in concrete has positive influence on mass and water absorption reduction and increases the compressive strength of the specimens The results also showed that the day compressive strength of the bacterial concretes is about more than that of the control specimens Moreover results in the second series of specimens showed that surface treatment of concrete specimens by bacteria reduces water absorption Also bacterial concrete in both series of the specimens have lower chloride penetration in comparison with control specimens Key Words Concrete bacteria magnesium sulfate environment surface treatment of concrete durability chloride penetration PDF created with pdfFactory trial version www pdffactory com

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افزايش دوام بتن در محيط سولفاتي به كمك باكتري

اصلاح سطحي بتن , نفوذ يون كلريد