The Effect of Petrographic Characteristics and Physico-Mechanical Properties of Aggregates on the Quality of Concrete

Abstract

This paper examines the effect of the aggregate type on concrete strength and more specifically how the petrographic characteristics of various aggregate rocks as well as their physico-mechanical properties influences the durability of C 25/30 strength class concrete. The studied aggregate rocks are derived from Veria-Naousa and Edessa ophiolitic complexes as well as granodiorite and albitite rocks from their surrounding areas in central Macedonia (Greece). Concretes are produced with constant volume proportions, workability, mixing and curing conditions using different sizes of each aggregate type. Aggregates were mixed both in dry and water saturated states in concretes. Six different types of aggregates were examined and classified in three district groups according to their physicomechanical properties, petrographic characteristics and surface texture. The classification in groups after the concrete compressive strength test verified the initial classification in the same three groups. Group I (ultramafic rocks) presents the lowest concrete strengths, depending on their high alteration degree and the low mechanical properties of ultramafic aggregates. Group II (mafic rocks and granodiorite) presents a wide range of concrete strengths, depending on different petrographic characteristics and mechanical properties. Group III (albite rocks) presents the highest concrete strengths, depending on their lowest alteration degree and their highest mechanical properties. Therefore mineralogy and microstructure of the coarse aggregates affects the final strength of the concrete specimens.

Dynamic Mechanical Properties and Visco-Elastic Damage Constitutive Model of Freeze–Thawed Concrete

“…In recent years, many researchers have studied the freeze–thaw resistance of concrete [ 3 , 4 , 5 , 6 , 7 ] and established corresponding freeze–thaw damage models [ 8 , 9 ]. For example, Petros Petrounias [ 3 , 4 ] and Wojciech Piasta et al [ 5 ] studied the effect of coarse aggregate performance on concrete under ordinary temperature and freeze–thaw conditions, respectively, and the results showed that the resistance of the aggregate to freezing and thawing was demonstrated to agree with the values of crushing resistance and the lowest contents of pores with diameters unsafe in terms of the freeze–thaw resistance. Bahram M. Taheri et al [ 6 ] evaluated the freeze–thaw durability of pervious concrete specimens using the JC446-91 test method and revealed that the conditions and number of cycles used in JC446-91 were inadequate to evaluate the freeze–thaw durability of pervious concrete, especially for strong mixes.…”

Application of Photocatalytic Concrete Paving Blocks in Poland—Verification of Effectiveness of Nitric Oxides Reduction and Novel Test Method

“…In concrete paving blocks, the dominant constituent is an aggregate, and as emphasized by Petrounias et al [ 28 ], aggregate has a major impact on a concrete’s properties. However, the goal of the research was to investigate the concrete pavement’s photocatalytic properties.…”

Durability of Blended Cements Made with Reactive Aggregates

“…In some cases, they react with the alkaline pore solution of the concrete. Accordingly, the alkali–silica reaction (ASR) occurs in concrete [ 8 ], which is a deleterious swelling reaction between the highly alkaline pore solution [ 9 ] and the amorphous reactive silica present in some common aggregates [ 10 ], as it draws water from the surroundings. This reaction is a two-step process: (i) alkalis react with the reactive silica present in the aggregate producing alkali-silica gel; (ii) such alkali–silica gel imbibes water and swell producing expansion.…”