Durability of alkali-activated slag/silica fume(AASS) concrete pavement

Document Type : Original Research

Authors
A. Mohammadi janaki 1
A. hassani 2
1 Student Tarbiat Modares University
2 Professor Tarbiat Modares University
Abstract
Roads are one of the most important and valuable assets of countries, and remarkable amounts are spent annually to repair and restructure them. The pavements are divided into two main groups of flexible pavements (asphalt pavements) and rigid pavements (concrete pavements). In Iran, mainly used asphalt pavements, which were formerly about 90 years old. Therefore, there are many reasons why the most important of them, according to most experts, is the use of the country from abundant oil resources and low initial costs in the construction of this type of pavement. In recent years, with the entry of bitumen as one of the main components of the asphalt composition of the commodity exchange and consequently the increase in the cost of manufacturing and manufacturing asphalt, as well as the development of cement production plants in the country and the creation of carbon dioxide (CO2), a suitable platform for the development of geo-polymeric concrete pavements in competition with asphalt pavements and concrete cement has been provided.

In addition to abbility of bearing and reducing the pressure caused by the vehicle wheels, the pavement layers should be durable against atmospheric and physical factors, including the natural elements of the freeze-thaw cycles, acids and sulfates. Th pavement must be able to withstand the durability and durability of the pavement and maintain its service over the lifetime specified.

These destructive effects led to more attention to the optimal use of resources, pozzolanic materials, and waste. In this regard, the use of ground granulated blast furnace slag and Silica fume in various industries such as road construction and building have been considered as a solution, however, practical, accurate and effective steps have not been taken yet. This research tried to present the materials and experiments carried out and to summarize them in order to eliminate the obstacles and obtain the necessary results for the use of alkaline concrete (geo-polymeric) in the manufacture of durable concrete veneers in the pavement.

The use of alkali-activated slag concrete with the replacement of Silica fume instead of silica in sodium silicate, in addition to the use of waste materials, enables the strength and durability of concrete pavement to be increased under freezing and thawing cycles, acid attacks and being sulfate.

In this study, alkali-activated slag concrete with different percentages of Silica fume was studied using The experiments of compressive and bending strength, durability under freeze-thaw cycles, sulfuric acid, and magnesium sulfate attacks. The results showed that the replacement of 30% silica fume instead of silica in sodium silicate, increasing the compressive strength to 43.8%, increasing the bending strength by 58.9%, increased the durability under freezing and thawing cycles by 78.2%, increasing durability against sodium sulfate to The rate of 57.1%, increase the durability against magnesium sulfate by 54.1%, and the reduction of pavement slab thickness by 20.8% compared with concrete cement.

Keywords

Subjects

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Modares Civil Engineering journal
Volume 19, Issue 4
November and December 2019
Pages 161-171