Influence of Pressure and Temperature on Compacted Plastic–Concrete Bending Strength

Demolished concrete and plastic waste are two increasingly aggravating problems. In this study, a novel method was proposed to simultaneously recycle concrete and plastic wastes by compacting concrete and plastic powders together under pressure and temperature. The influence of compression pressure and temperature as well as the mixture proportion on the bending strength of specimens was investigated. The results showed that pressure and temperature had a positive effect on the specimen strength; however, the molding temperature should not exceed the melting temperature of plastic. The proportion of plastic had a minimal effect on the bending strength of the specimen when plastic accounted for 25%–75% of the overall mass of the test piece.

Experimental Study of the Bending Strength of Recycled Concrete and Wooden Waste by Heating Compaction

A large amount of concrete waste is generated around the world and its recycling is an urgent issue. In this research, a new approach to recycle concrete waste with wooden waste was studied. Concrete and wooden wastes were crushed, mixed, and heat compacted to produce plates with different water contents and mix proportions at various temperatures, pressures, and durations of compaction. The bending strength of the plates was measured after compaction. The result indicated that with an increase in the percentage of wooden waste in the mixture, pressure, or temperature improved the bending strength. The increase in water content reduced the bending strength. Most of the products exhibited higher bending strength than that of ordinary concrete.

Intelligent Replaced of Natural Aggregate and Cement with Recycled Concrete Aggregate, Rice Husk Ash

Annually a huge amount of construction and demolition (C&D) waste is generated. It becomes really harmful and posing an adverse effect to the environment, increasing waste generation have demanded the need for recycling the C&D Waste. Similarly, as cement accounts for 10% global CO2 emissions, it is imperative to reduce the embodied CO2 of concrete. Thus, the sustainability of concrete is a major issue which needs to be addressed. Ways of achieving this is to recycle concrete waste back into concrete to reduce waste and use of supplementary cementitious to reduce CO2 emissions. This research aims to take a two-pronged approach by investigating the effect of pozzolanic replacement with fixed proportion of recycle aggregates to evaluate the strength and potential structural application. In this research carried out M40 mix design and rice husk ash were substituted for cement at level of 5, 10, 15, 20% by using a fixed ratio of 10, 20,30% recycle concrete aggregate (RCA). Compression test, Split Tensile Test, Flexural Test and Rapid Chloride penetration test were conducted on specimens of Grade M40, for compression test the cube was cured for 28 days and 90 days for durability (RCPT). All RCA mixes and up to 15% RHA replacement satisfied M40 criteria at 90 days, however the 20% RHA replacement mix was close to achieving this. Thus, the finding of this study indicates the use of concrete containing 30% RCA and 15% RHA can be substantially reduce waste and embodied CO2 without compromising on strength and durability parameters.