The effect of synthetic zeolite admixture on the durability of concrete paving blocks

Giedrius Girskas,Džigita Nagrockienė,Gintautas Skripkiūnas

doi:10.3846/bjrbe.2016.25

Giedrius Girskas, Džigita Nagrockienė + Show 1 more

Open Access

https://doi.org/10.3846/bjrbe.2016.25

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Abstract

Concrete paving blocks that were started to be used in the last century have become very popular. They became an alternative to the natural stone. Concrete paving blocks are used for the paving of pedestrian and vehicle zones. Durability is one of the main characteristics in the production of high-quality concrete paving blocks in the Baltic region climate zone. The article describes tests with concrete paving blocks, the top layer of which contains 5% of synthetic zeolite admixture obtained by means of low temperature synthesis in laboratory conditions. This zeolite admixture is obtained from aluminium fluoride production waste. The durability of concrete paving blocks was tested according to abrasion resistance, tensile splitting strength, absorption and frost resistance. The test results revealed that 5% of zeolite admixture added to the top layer of concrete paving blocks reduce the absorption, increase the tensile splitting strength by more than 10%, and decrease abrasion by 6.5%. The zeolite admixture used in concrete paving blocks reduces the scaling about 4 times after 28 freeze-thaw cycles when 3% NaCl is used as the freezing solution. The tests revealed that synthetic zeolite admixture can be used in concrete elements production by means of vibropressing (pavement elements) to increase their durability.

Highlights

Concrete paving blocks are widely used in Europe
The goal of the testing described in this article is to determine the changes in density, water absorption progress, abrasion resistance, splitting tensile strength and freeze-thaw resistance of concrete paving blocks, the top layer of which contains up to 5% of synthetic zeolite admixture
Detailed tests with concrete paving blocks containing synthetic zeolite admixture in the top layer showed that zeolite admixture reduces water absorption, increases tensile splitting strength, abrasion resistance and reduces the surface scaling 4 times after 28 freeze-thaw cycles with 3% NaCl solution used as de-icing agent

Summary

Introduction

Concrete paving blocks are widely used in Europe. In Northern European climate conditions these blocks are often exposed to high humidity and freeze-thaw cycles, the number of which has a great effect on the durability of the paving blocks. According to Nagrockienė et al (2014) after 28 freezethaw cycles the scaling of concrete specimens significantly decreases when 10% of zeolite is added to Portland cement concrete They found that synthetic zeolite admixture changes the morphology of hardened cement paste: Ca(OH) and ettringite contents reduce, whereas C-S-H phase increases and influences the increase in density of hardened cement paste, its strength and freeze-thaw and de-icing salts resistance (Nagrockienė et al 2014). The goal of the testing described in this article is to determine the changes in density, water absorption progress, abrasion resistance, splitting tensile strength and freeze-thaw resistance (using 2 methods) of concrete paving blocks, the top layer of which contains up to 5% of synthetic zeolite admixture

Materials

Specimens formation and test methods

Test results

Findings

Conclusions