Topic
Aggregate (composite)
About: Aggregate (composite) is a research topic. Over the lifetime, 31015 publications have been published within this topic receiving 354178 citations.
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TL;DR: In this paper, the results of research on structural recycled high performance concrete (RHPC) are presented, where the aggregate obtained from crushing of such structures retained some binding abilities as may be activated by means of silica fume or fly ash admixtures.
Abstract: Recently, aggregates derived from demolished concrete structures were of relatively low strength, and applications were of secondary importance. Since a short time, the necessity of demolition of structures with strong concrete, like building frames or bridge beams, has appeared and created the source of recycled aggregate of quite new generation. Besides of obvious environmental aims recycling of concrete has gained new economical aspects. Concrete in responsible structures, with strength of 40–70 MPa for instance, was originally mixed from aggregate of good quality, e.g. granite or basalt, and with large amount of cement. The aggregate obtained from crushing of such structures retained some binding abilities as may be activated by means of silica fume or fly ash admixtures. Generally, such aggregates are different from natural and, consequently, concrete made with use of them has specific properties. The results of research on mechanical properties of structural recycled high performance concrete (RHPC) are presented.
560 citations
TL;DR: In this article, a fine glass powder (GLP) was used for incorporation into concrete as a pozzolanic material to suppress the alkali reactivity of coarser glass particles as well as that of natural reactive aggregates.
544 citations
TL;DR: In this paper, the durability of Portland cement systems incorporating supplementary cementing materials (SCM; silica fume, low and high-calcium fly ash) is investigated.
534 citations
TL;DR: It is concluded that utilization of RAC for low-to-middle strength structural concrete and non-aggressive exposure conditions is technically feasible and the environmental impacts are slightly larger for RAC than for NAC but the total environmental impacts depend on the natural and recycled aggregates transport distances and on transport types.
528 citations
TL;DR: In this paper, different concrete mixes with increasing rates of substitution of fine natural aggregates with fine recycled aggregates from crushed concrete were prepared and tested, and the results were then compared with those for a reference concrete with exactly the same composition and grading curve, but with no recycled aggregate, drawing some conclusions on the feasibility of using this type of aggregate in structural concrete.
Abstract: Fine recycled aggregates are seen as the last choice in recycling for concrete production. Many references quote their detrimental influence on the most important characteristics of concrete: compressive and tensile strength; modulus of elasticity; water absorption; shrinkage; carbonation and chloride penetration. These two last characteristics are fundamental in terms of the long-term durability of reinforced or prestressed concrete. In the experimental research carried out at IST, part of which has already been published, different concrete mixes (with increasing rates of substitution of fine natural aggregates – sand – with fine recycled aggregates from crushed concrete) were prepared and tested. The results were then compared with those for a reference concrete with exactly the same composition and grading curve, but with no recycled aggregates. This paper presents the main results of this research for water absorption by immersion and capillarity, chloride penetration (by means of the chloride migration coefficient), and carbonation resistance, drawing some conclusions on the feasibility of using this type of aggregate in structural concrete, while taking into account any ensuing obvious positive environmental impact.
516 citations