Properties of Recycled Aggregate Concrete

Jiaxin Dang^*
*Correspondence: Jiaxin Dang, Weibin Wen School of Civil Engineering, Central South University, P.R, China, Email:

Introduction

The capacity of concrete made entirely of recycled aggregate to meet the durability and strength criteria of various applications. Concrete's strength and durability are influenced by physical and mechanical qualities such as aggregate strength, gradation, absorption, specific gravity, form, and texture. The grade of recycled aggregate is often determined by the loading and exposure conditions of demolished constructions. As a result, the experimental programme concentrated on evaluating the recycled aggregate's physical and mechanical qualities during a six-month period. In addition, the characteristics of concrete made from fine and coarse recycled material were assessed. The results of several concrete mixes made entirely of recycled aggregates were compared to those of a control mix. SEM was used to look at the microstructure of some of the blends. The findings revealed that if a high packing density is attained, concrete with appropriate strength and durability can be created.

The structure and the environment are both affected by construction materials. The structure's strength is determined by the materials used in its construction. Because construction materials have an impact on the environment, they must be environmentally friendly. The answer lies in the reality that only if we take care of nature will it augment and assist humanity. Our way of life should be in tune with the natural world. Old structures are frequently demolished to make way for new ones, and the debris from these demolished structures - the majority of which is concrete – is dumped and never repurposed, negatively impacting the land's fertility. As a result, researchers, scientists, and builders are all looking for environmentally friendly building materials.

Description

The volume of mortar in recycled aggregate concrete is bigger than that of natural aggregate concrete due to the adhering mortar linked to recycled aggregate, but the volume of aggregate is smaller. The deterioration of the properties of recycled aggregate concrete may be caused by changes in the ratio of the raw materials that make up concrete, but it can be controlled using the equivalent mortar volume mix design method, which treats adhered mortar in recycled aggregate as a mortar rather than an aggregate. Starting with the mechanical qualities and durability performance of fresh concrete, such as slump, density, and air content, the mechanical properties and durability performance of hardened concrete are reviewed. It also sheds light on the mix design's environmental advantages.

Size of aggregate

Crushed concrete must be treated to achieve the desired sizes. One of the elements that affect the strength of concrete is the manner of crushing it (mechanical or manual) to produce coarse aggregate for the formation of new concrete. According to reports, coarse aggregate that meets specifications can be manufactured. Fine aggregates, on the other hand, are bigger and more angular than those used in concrete manufacturing. As a result, crushed concrete aggregate produces concrete that is harsh and difficult to work with. This problem could be solved by adding some natural sand. It is possible to use recycled aggregate without washing it. Finally, the amount of adhering mortar is affected by the crushing technique and the dimension of the recycled aggregate. The amount of mixing water required for adequate workability is mostly influenced by the aggregate particle grading. If the proportion of particles in the concrete is increased, the water need rises, resulting in poorer concrete strength unless the cement content is increased. Since of its high absorption capacity, recovered sand is not suggested for usage because it shrinks. The density of crushed concrete aggregate is lower than the density of natural aggregate.

Water absorption

The capacity of recycled aggregate to absorb water is greater than that of natural aggregate. It is one of the most important characteristics that differentiate recycled aggregate from unprocessed material. The ability of recycled aggregate to absorb water has an impact on the characteristics of both fresh and cured concrete. Because of its absorption capacity, recycled sand will be avoided, as it would undoubtedly cause shrinkage. The absorption capacity of recycled aggregates affects the workability of recycled aggregate concretes. The presence of pollutants in recycled aggregate reduces the strength of concrete made with it.

Strength variations

The strength of concrete formed from crushed concrete aggregate is generally lower than that of concrete made from natural material. Concrete made from recycled coarse aggregate and natural fine aggregate has a strength loss of 5 to 24 per cent. The strength of crushed concrete, as well as the water-to-cement ratio of crushed and new concrete, influenced this. The percentage of recycled coarse and fine aggregate used in concrete varies between 15 and 40%. The strength variation of recycled aggregate concrete is greater than that of natural aggregate concrete. In order to get the same workability and compressive strength as conventional concrete, it would be necessary to add extra cement to recycled aggregate concrete produced entirely of recycled aggregate. Any variation in the manufacture of concrete or the qualities of the ingredients employed results in a variance in the strength of the final product [1-5].

Future Prospective

Recycled aggregate concrete has lower shear strength than regular concrete. This is because, for example, recycled aggregate from fielddemolished concrete is typically weaker than natural aggregate. When recycled coarse aggregates are utilised, the strength of the concrete is reduced by 10% on average.

Acknowledgement

None.

Conflict of Interest

The author shows no conflict of interest towards this manuscript.

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