The Effect of Fine and Coarse Recycled Aggregates on Fresh and Mechanical Properties of Self-Compacting Concrete

Abstract

Today, the use of recycled aggregates as a substitute for a part of the natural aggregates in concrete production is increasing. This approach is essential because the resources for natural aggregates are decreasing in the world. In the present study, the effects of recycled concrete aggregates as a partial replacement for fine (by 50%) and coarse aggregates (by 100%) were examined in the self-compacting concrete mixtures which contain air-entraining agents and silica fumes. Two series of self-compacting concrete mixes have been prepared. In the first series, fine and coarse recycled mixtures respectively with 50% and 100% replacement with air entraining agent were used. In the second series, fine recycled (with 50% replacement) and coarse recycled (with 100% replacement) were used with silica fume. The rheological properties of the self-compacting concrete (SCC) were determined using slump-flow and J-ring tests. The tests of compressive strength, tensile strength, and compressive stress-strain behavior were performed on both series. The results indicated that air-entraining agent and silica fume have an important role in stabilization of fresh properties of the mixtures. The results of tests indicated a decrease in compressive strength, modulus of elasticity, and energy absorption of concrete mixtures containing air entrained agent. Also, the results showed that complete replacement (100%) with coarse recycled material had no significant effect on mechanical strength, while replacement with 50% fine recycled material has reduced compressive strength, tensile strength, and energy absorption.

End-of-Life Materials Used as Supplementary Cementitious Materials in the Concrete Industry

“…Meanwhile, a lot of EOL materials are disposed of in open fields as landfill. One example of this kind of waste is construction and demolition debris with enormous potential for recycling as a profitable recycled concrete aggregate (RA) [2,3]. RA can be found in almost all developed and developing countries as a result of the demolition of older buildings and structures.…”

Experimental Study on the Workability and Stability of Steel Slag Self-Compacting Concrete

“…The segregation resistance is often considered as the index of stability of SCC, which also can be classified as static stability and dynamic stability. At present, the evaluation and test methods of the workability of SCC mainly includes a slump flow (SF) test incorporating slump flow time (T500) measurements [13][14][15][16][17][18][19][20][21][22][23][24][25][26], a V-funnel test [14,15,17,[19][20][21][22]24,26], a L-box test [13,15,19,21,23,24,26], a U-shape meter test [14,17,22], and a J-ring test [15][16][17][18][19]24,25], etc. Stability tests conducted for SCC mixture involved a sieve analysis test [15,17,20,25], flow table test [27], segregation probe test [20], and static settlement column test…”

Experimental Study of Utilizing Recycled Fine Aggregate for the Preparation of High Ductility Cementitious Composites

“…Lederer et al [19] reported that the use of crush dust can form a good particle gradation with cement, fly ash and RFA and having a good filling effect, which then increases the compressive strength of mortar. Nili et al [20] reported that concrete with 50% RFA replacement has reduced compressive strength, tensile strength, and energy absorption. Liang et al [21] found that the compressive strength and elastic modulus of concrete containing both recycled coarse aggregate and RFA is lower than that of concrete containing natural coarse aggregate and RFA after enduring high temperatures.…”