Effects of long-term magnesium sulfate crystallisation tests on abrasion and durability of andesite aggregates

Abstract

The durability of aggregates against salt weathering is calculated after five cycles of immersion in a magnesium sulfate solution followed by drying according to the relevant European standard (EN 1367-2: 2010). The aim of the study is to investigate the long-term durability of aggregates by increasing the number of cycles of the salt crystallization test from the standardized five to a maximum of 35. Three andesite types from Hungarian quarries were tested representing three different localities. The weight loss of the specimens was determined after every 5-cycle set. Results were documented for three size-fractions 10.0/11.2 mm, 11.2/ 14.0 mm and the 10.0/14.0 mm, respectively. Relationships between immersion-drying cycles and magnesium sulfate values were described by the Pearson-coefficient. According to the test results, the magnesium sulfate values followed linearly increasing tendencies in the course of the long-term salt crystallization tests. Parallel to the salt-weathering tests, the changes in the mechanical properties of the salt-attacked aggregates were also detected by micro-Deval tests (EN 1097-1: 2012). The changes in micro-Deval coefficients were calculated in the form of a decay factor as a function of sulfate cycles. The results suggest that the micro-Deval coefficient does not rise after a certain salt cycle; i.e. higher number of salt-crystallisation cycles does not necessarily reduce the micro-Deval coefficient of studied andesite lithologies.

Potential of Natural and Recycled Concrete Aggregate Mixtures for Use in Pavement Structures

“…The possibility of reducing water absorption in the designed granular mixtures is significant. Silicate aggregates usually have good resistance to frost [5]. However, over time, the technical properties of aggregates can change differently.…”

“…Thus, for example, amphibole andesite is progressively decomposed in the long-term salt crystallisation test, while micro-Deval initial increase, and then reach a constant value. Pyroxene andesite is also decomposed, due to a salt-action, but aggregate wear remains unchanged [5].…”

“…Over the last decades, numerous researchers have observed a strong relationship between mineral composition, micro-assembly and rock alterations on the one hand and wear resistance (micro-Deval coefficient) and various aggregate strength parameters on the other hand [4,5]. Others investigated the relationships between different technical properties of aggregates in order to establish their mutual correlations [6].…”

Wear and Fragmentation Resistance of Mineral Aggregates—A Review of Micro-Deval and Los Angeles Tests

“…The review results also suggest that the mineral composition, structure, and size of mineral components definitely have a significant influence on the resistance to wear and fragmentation. Interestingly, the majority of publications related to research into aggregate wear and fragmentation resistance tests address issues of mutual relationships and correlations between aggregate properties [ 3 , 11 , 14 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 ].…”

“…A similar influence of magnesium sulfate on wear in micro-Deval tests was confirmed by Fournari and Ioannou [ 11 ], Durmeková et al [ 43 ], and Wu et al [ 101 ]. Czinder and Török [ 42 ] observe that the influence of magnesium sulfate may cause a loss of abrasion hardness of as much as 35%.…”