Recycled aggregate from C&D waste & its use in concrete – A breakthrough towards sustainability in construction sector: A review

Properties and composition of recycled aggregates from construction and demolition waste suitable for concrete production

Construction and Demolition (C&D) waste constitutes a major portion of total solid waste production in the world, and most of it is used in land fills. Research by concrete engineers has clearly suggested the possibility of appropriately treating and reusing such waste as aggregate in new concrete, especially in lower level applications. This paper discusses different aspects of the problem beginning with a brief review of the international scenario in terms of C&D waste generated, recycled aggregates (RA) produced from C&D waste and their utilization in concrete and governmental initiatives towards recycling of C&D waste. Along with a brief overview of the engineering properties of recycled aggregates, the paper also gives a summary of the effect of use of recycled aggregate on the properties of fresh and hardened concrete. The paper concludes by identifying some of the major barriers in more widespread use of RA in recycled aggregate concrete (RAC), including lack of awareness, lack of government support, non-existence of specifications/codes for reusing these aggregates in new concrete.

Use of aggregates from recycled construction and demolition waste in concrete

A review of recycled aggregate in concrete applications (2000–2017)

Mechanical properties of brick aggregate concrete

The recycling of demolished masonry rubble as coarse aggregate in new concrete represents an interesting possibility at a time when the cost of dumping such material is on the increase. With the number of readily accessible disposal sites around major cities in the world decreasing in recent years and disposal volume and maximum sizes of waste being restricted, the cost of dumping construction and demolition debris has increased substantially over recent years. This cost increase has been further fueled in the United Kingdom and other countries by the introduction of a landfill tax by governments and local authorities for the dumping of such waste. Due to the growing concerns over the environmental impact of aggregate extraction and the continued rise in aggregate demand, it is clear that the building and construction industry is ready to accept recycled and secondary aggregates. This paper provides a review of previous work covering the use of demolished waste, especially crushed brick, as the coarse aggregate in new concrete.

Recycling of Demolished Masonry Rubble as Coarse Aggregate in Concrete: Review

This paper provides the results of an experimental investigation into the use of crushed new clay brick as coarse aggregate in producing concrete. The present investigation is the first phase of a two-phase program to study the effects of using recycled masonry aggregate (predominately made of clay brick) with its impurities on the properties of fresh and hardened concrete. Four different types of new clay bricks with different compressive strengths were used in the investigation. Several physical and mechanical properties of fresh and hardened concrete produced from crushed clay brick aggregates were determined and compared to concrete produced using granite as a proven aggregate.

Using Crushed Clay Brick as Coarse Aggregate in Concrete

The testing described in this paper was performed to establish the physical and mechanical properties of new and recycled crushed clay brick aggregates for use in portland cement concrete (PCC). Various physical and mechanical properties of eight different types of aggregates were determined and compared with the limits set out in the British Standards for aggregate from natural sources used in concrete. The results were also compared with granite aggregate that has been proved to be a good natural aggregate for producing PCC. The results showed that most of the crushed clay-brick aggregates tested can be used in producing PCC for low-level civil engineering applications and that some kinds of brick aggregate possess good physical and mechanical properties that qualify them for producing high-quality concrete.

Properties of New and Recycled Clay Brick Aggregates for Use in Concrete

This paper presents the results of an experimental investigation into the effects of high temperatures on the properties of concrete made with crushed clay bricks as the coarse aggregate. Two types of brick of different strength were crushed to coarse aggregate that was used to produce concretes of different strength. Natural granite aggregate was also used to produce concretes in order to compare results. The paper presents the results for brick unit uniaxial compressive strength, aggregate impact value, aggregate relative density, brick and aggregate water absorption, aggregate porosity, concrete density, and concrete strength before and after exposure to high temperatures. The results showed that concrete could be produced using crushed clay bricks as the coarse aggregate and at high temperatures clay brick concrete preformed similar or even better than granite concrete.

Performance of Brick Aggregate Concrete at High Temperatures

The bond strength between masonry units and mortar has been of considerable interest to researchers for some time. The flexural bond strength of masonry in particular is needed for the design of masonry walls subjected to horizontal forces applied normal to the face of the wall, such as wind forces. Researchers and standards have suggested different kinds of specimens and test procedures to determine the flexural bond strength. These include the test on wallettes (small walls), the bond wrench test, the Brench test, the direct tensile test, and the crossed couplet test. Each of these tests has its own drawbacks and problems. This paper presents a test method to determine the flexural bond strength, ffb , by bending. The test could be used for laboratory research to investigate the many factors affecting bond strength and also for deriving design values for masonry standards. The specimen is constructed from two brick units in a Z-shaped configuration, and three-point loading induces a flexural bond failur...

Fouad M. Khalaf

Papers

Recycling of Demolished Masonry Rubble as Coarse Aggregate in Concrete: Review

Using Crushed Clay Brick as Coarse Aggregate in Concrete

Properties of New and Recycled Clay Brick Aggregates for Use in Concrete

Performance of Brick Aggregate Concrete at High Temperatures

New Test for Determination of Masonry Tensile Bond Strength