Bameri M, Rashidi S, maghsoudi M, manouchehri M. Laboratory evaluation of the properties of eco-friendly four-component concretes containing silica fume, glass powder and ground granulated blast furnace slag. MCEJ 2022; 22 (4) :203-216
URL:
http://mcej.modares.ac.ir/article-16-60616-en.html
1- Master of Civil Engineering in Construction Management, Department of Civil Engineering, Islamic Azad University, Karaj Branch
2- Master student in structural engineering, Department of Civil Engineering, Islamic Azad University, Kerman Branch
3- Assistant Professor, Department of Civil Engineering, University of Jiroft , maghsoudi_mohammad@ujiroft.ac.ir
4- R&D Manager of Kerman Traffic Engineering Company
Abstract: (1835 Views)
Nowadays, concrete is used as a widely used material in different industries. Depending on the usage of concrete, different properties can be expected from it. Plentiful usage of concrete in other industries such as bridge construction, landscaping, construction, harbors, docks, and special structures has made this valuable material the center of attention of many researchers. Depending on the type and place of using concrete, this material has limitations and problems. Destruction of concrete in the long term is one of the factors causing damage to the industrial cycle and economy of countries. The high durability and reliability of concrete reduce damage to the environment and increase the service life of structures. Important factors are the useful life of concrete structures, environmental conditions, and concrete quality. The attack of sulfates on concrete is one of the critical factors in reducing the life of the structure and the durability of concrete. Sodium, magnesium, and calcium sulfates are salts usually found in soils and groundwater and react with different phases of hydrated cement paste, such as hydrated alumina, hydrated monosulfate, and calcium hydroxide, to produce needle-shaped crystals of ettringite and calcium sulfate (gypsum). The volume of these crystals is greater than the volume of cement hydration products, so they cause internal stress and cracking in hardened concrete. Magnesium sulfate is more damaging than other sulfates because it destroys calcium silicate hydrate (C-S-H). In the attack of magnesium sulfate and the conversion of Ca(OH)2 to gypsum, it is accompanied by the simultaneous formation of Mg(OH)2 (brucite), which is insoluble and reduces the alkalinity of the system. In the absence of hydroxyl ions in the pore solution, the stability of C-S-H in the system is reduced and attacked by the sulfate solution. The ultimate product of this substitution reaction is the magnesium silicate hydrate, the formation of which is associated with the loss of the cementitious characteristic. Permeability and porosity are the most critical factors in increasing the resistance of concrete against sulfate attack. This study evaluated weight and compressive strength changes after placing in magnesium sulfate solution for six designs of concrete mixes containing silica fume, glass powder, and steel slag. In addition, the depth of water penetration under pressure and water absorption tests were performed to evaluate the permeability of concrete. The results showed the proper performance of glass powder and steel slag against magnesium sulfate attack and reduced the depth of water penetration. Changes in the weight and compressive strength of concrete against magnesium sulfate attack depend on the properties of supplementary cementitious materials, their replacement amount, and concrete porosity.
Article Type:
Original Research |
Subject:
Civil and Structural Engineering Received: 2022/04/5 | Accepted: 2022/06/15 | Published: 2022/07/1