The Effect of Chemical Composition of Ultramafic and Mafic Aggregates on Their Physicomechanical Properties as well as on the Produced Concrete Strength

Paraskevi Lampropoulou,Nikolaos Koukouzas,Petros Petrounias,Konstantin Hatzipanagiotou,Panagiota Giannakopoulou,Aikaterini Rogkala,Basilios Tsikouras

doi:10.3390/min10050406

Paraskevi Lampropoulou, Nikolaos Koukouzas + Show 5 more

Open Access

https://doi.org/10.3390/min10050406

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Abstract

This study examines how the chemical composition of ultramafic and mafic rocks effects their physicomechanical properties and therefore how influences the concrete strength of the produced concrete specimens. For this scope, ultramafic (Group I) and mafic rocks (Group II) derived from the Veria–Naousa and Edessa ophiolite complexes (Greece) were selected in order to identify their chemical composition and their engineering properties according to international standards. Additionally, representative rocks were used as concrete aggregates in order to produce concrete specimens, whereas their mechanical strength was calculated. A geochemical index (Ga) was proposed and correlated with the engineering properties of the examined rocks as well as with the widely used alteration degree LOI (loss on ignition). Correlation diagrams between engineering properties and the proposed geochemical index (Ga) have showed that these properties were strongly influenced by the alteration processes expressed via Ga index. More particularly, mainly serpentine in ultramafic and chlorite in mafic rocks, minerals indicators for the alteration of ultramafic and mafic rocks, respectively, seem to determine their engineering properties. Concerning the mechanical strength of the produced concrete specimens, the results have showed that the increasing values of Ga index negatively effect concrete strength.

Highlights

Engineering projects, in which natural aggregate rocks are used as raw materials, strongly influenced by their physicomechanical properties which are directly correlated with the particular characteristics of rocks
In this study, crushed ultramafic and mafic aggregates rocks derived from the referred ophiolite complexes were collected, during the research in the field area, in order to be analyzed according to their petrographic features, geochemistry, physicomechanical properties in the laboratory as well as concrete specimens were produced by these aggregates which were mechanically tested in a stage
Concrete strength values vary from 25 to 32 Mpa in the examined specimens and in those specimens made by mafic aggregate rocks (Group II) display better mechanical strength than those made by ultramafic aggregates (Group I)

Summary

Introduction

Engineering projects, in which natural aggregate rocks are used as raw materials, strongly influenced by their physicomechanical properties which are directly correlated with the particular characteristics of rocks. Several researchers have studied the effect of mineralogical composition, textural characteristics and chemical composition of various types of aggregate rocks in order to predict their mechanical behavior when used in various construction applications [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18]. Minerals 2020, 10, 406 evaluation/quantification of alteration degree and on the influence of alteration of aggregate rocks in their engineering properties [4,5,18,19] and in their construction applications [4,18]. First-order changes to the major element composition of peridotites induced by serpentinization are the addition of 10–12 wt%

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