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MPhil in Engineering for Sustainable Development

global challenges, engineering solutions

Studying at Cambridge

Theerawat Runguphan

Effect of contaminants in recycled aggregate on concrete strength performance

Theerawat Runguphan

Effect of contaminants in recycled aggregate on concrete strength performance

Increased environmental awareness has put pressure on the construction industry to find new ways to re-use construction materials rather than disposing them as waste.  The production of concrete with recycled aggregate from such re-use presents the most desirable form of a closed life cycle of concrete as construction material.  This practice represents a potential value-added outlet for the material, is often economically viable and environmentally beneficial.  While accepting the need to promote the use of recycled aggregate in wider applications, it is necessary that aggregate meet the quality requirements set in relevant standards for its particular use.  This dissertation presents the results of an experimental study undertaken on recycled aggregate concrete mix to examine the effect of presence contaminants on the compressive strength performance in new concrete.
The result from this research essentially suggests that acceptable quality concrete can be produced using recycled aggregate even in the presence of high level of contaminants.  Although the general accepted opinion that the inclusion of contaminants in recycled aggregate causes a  strength reduction does hold true, the research shows that recycled aggregate concrete with combined contaminants (timber, plastic and plaster), each at 5% by recycled aggregate weight (totalling 15%), attained 32Mpa at 28 day which exceed 90% confidence level of the designed strength as of Road Note No 4.