This document reviews the effect of concrete demolition waste on the strength and durability of concrete. It discusses advantages like reduced costs and disadvantages like reduced strength. The literature review found that up to 60% recycled aggregates can be used to replace virgin aggregates with comparable concrete properties. Recommendations include using clean recycled aggregates up to 60%, removing mortar, controlling water, and using recycled concrete for non-critical structures only. The conclusion is that debris-filled recycled aggregates will negatively affect concrete properties and durability.

1. REVIEW OF THE EFFECT OF
CONCRETE DEMOLITION WASTE
ON CONCRETE’S
STRENGTH AND DURABILITY
By
PHILA DERRICK CIRA
Student Number: 63 077 167
Contact No: 073 335 4460
E-Mail: 63077167@mylife.unisa.ac.za
Assignment number: 02
Assignment Unique No: 857443

2. Contents
 Introduction
 Background
 Aim & Objectives
 Advantages of using CD waste
 Disadvantages of using CD waste
 Literature Review
 Recommendations
 Conclusions
 Annexures

3. Introduction
Concrete demolition waste is the rubble produced after demolition of
normally old structures. This waste is a form of aggregates (course
and fine). It is therefore utilized on many countries as a concrete
ingredient.
It is very much significant to consider the strength and durability when
using concrete demolition waste. This ensures that certain structure to
be built will meet the acceptable properties of concrete and also be
able to function throughout its design life.

4. Background
The idea of recycling of construction and demolition waste (C&DW) is
not a new one, but one that many developed countries such as those
in the European Union and Japan have implemented very successfully
for a number of years now. Various studies have shown that the
C&DW waste streams in Europe alone in the late 90’s stood at around
200-330 million tons per year. This type of waste was generally made-
up of around 67% of masonry and old concrete rubble and it is
assumed that the waste make-up is the same in developed countries
worldwide.

5. Background continued…
The construction and demolition waste (C&DW) stream in South Africa
(SA) alone is estimated at around 5-8 million tons. This shows that
there is a massive opportunity for growth in the recycling industry
worldwide as well as in SA with regards to the recycling of C&DW. SA
still has vast open spaces and natural aggregate resources are still
available, therefore it is not surprising that SA is lagging behind in
terms of its development of measures to promote the recycling of
C&DW.

6. Aim & Objectives
The aim and objective is to carry out a research of various
experiments performed by researchers and analyse the effectiveness
of concrete demolition waste being utilised to achieve the desired
strength and durability of concrete.
Also to make recommendations on how and where the concrete
demolition waste can be used as an ingredient of concrete.

7. Advantages of using CDW
 Reduction in the usage of virgin materials
 Cost effective as compared to the natural crushes aggregates
 Reduced transportation cost of material, as demolition waste could
be used on the same site or in nearby area.
 60% recycled aggregates can be used to replace virgin aggregates
as the final concrete produced is comparable to the one made with
normal materials.

8. Disadvantages of using CDW
 High reduction of Compressive strength is attained when using
recycled aggregates.
 Tensile and flexural strength is affected and creates a major
problem to the structure as a whole.
 High water absorption due to presence of debris sticking on
crushed concrete.
 High porosity of RC has been observed and causes cracks.
 Consistency of concrete is greatly affected due to over fine
aggregates

9. Literature Review
 Recycled aggregates are extensively used construction material
and upon usage, appropriate test needs to be performed to
evaluate the properties of the concrete to be produed.
 Recycled aggregate concrete as a form of concrete demolition
waste has a crushed sound and clean waste concrete of at least
95% by weight of concrete with typical total contamination lower
than 1% of the bulk mass
 Up to 60% of natural crushed coarse aggregate can be replaced
with coarse recycled aggregate to produce moderate properties of
the concrete

10. Literature review continued….
 The same procedures for testing materials is carried out as
stipulated in the SANS for example for cube test SANS 5863:2006,
Concrete tests, Compressive strength of hardened concrete
 The concrete produced from recycled aggregates cannot be used
on any concrete structure, The suitable areas of usage is judged by
the properties of produced concrete form recycled aggregates.
 Upon the usage of crushed concrete aggregates, it shall be
ensured that aggregates are free from mortar, wood, plastics and
any form of debris.

11. Recommendations
 Clean recycled aggregates shall be used
 Up to 60% of recycled material may be incorporated to replace
normal crushed aggregates.
 Mortar must be removed from concrete to control water absorption.
 W:C is proportional to the compressive strength, therefore
excessive water should not be used.
 Over fine sand from demolition waste should be discarded as they
undermine the consistency of concrete.

12. Recommendations continued…
 The particle shape of crushed aggregate shall be rounded to obtain
a well dense material not a high voided material.
 Extra cement is recommended to bind irregular particle shape.
 This type of concrete shall be on non-critical structures like fills,
roads embankments, stoeps, residential ground surfaces, hoarding,
etc.

13. Conclusions
It can be concluded that to use of recycled aggregates from the
demolition of an old structure containing debris, which has little control
over the recycling process will negatively affect the properties, as well
as the durability of concrete.
The essence of this research projects was fundamentally to equip
myself as a student to learn and to carry out an appropriate research
of the most widely used construction material. This has been a great
opportunity and great experience to have myself learnt the effects of
concrete demolition waste on the strength and durability of concrete.

14. References
 The use of recycled Building materials a aggregate in concrete, EP Kearsely & HF Mostert, Department of Civil Engineering, University
of Pretoria, Concrete Beton Journal No. 132 November 2012 pp. 8-12
 Owens, G. 2013. Fundamentals of concrete. 3rd edition. Midrand: Concrete Institute.
 Fulton’s Concrete technology, edited by Gills Owen, 9th edition, Cement & Concrete Institute, Midrand, South Africa, 2009 pp. 54
 Hasan, Sahan Arel and Ertug Aydin , Use of Industrial and Agricultural Wastes in Construction Concrete , ACI MATERIALS JOURNAL,
Title No. 115-M06, pp1
 Handbook of Recycled Concrete and Demolition Waste, edited by Joao Labrincha Cambridge, UK, 2013
 Recycling and reuse of construction and demolition waste: sustainable approach A. Bansal*, G. Mishra and S. Bishnoi, Indian Institute
Of Technology Delhi, New Delhi, India 2013
 An Experimental Study of Durability Aspects of Recycled Aggregate Concrete by Smitha Yadav, Snehal Pathak, World Academy of
Science, Engineering and Technology International Journal of Civil and Environmental Engineering, Vol:12, No:3, 2018 pp. 313-322
 An Introduction To Recycled Aggregate Concrete: Production And Applications
 Piyush Sharma 2015, Department Of Civil Engineering, Amity School of Engineering & Technology, Amity University, Haryana, India
 Merlet, J.D. and Pimienta, P. (1994), "Mechanical and Physico- Chemical Properties of Concrete Produced with Coarse and Fine
Recycled Concrete Aggregates," Demolition and Reuse of Concrete and Masonry, Rilem Proceeding 23, E&FN Spon, pp. 343-353.
 South African National Standards: SANS 5863:2006, Concrete tests, Compressive strength of hardened concrete
 G. Parrot,2005: Reinforced Concrete Design to SANS 10100:1-2000
 Durability performance of structural concrete made with coarse recycled concrete aggregates, Wayne dodds, Chris Goodier,
Loughborough University, leicestershire, UK, (conference paper https://dspace.lboro.ac.uk/2134/23683 )
 South African construction and demolition waste procedure and its sourced material effects on concrete, Johannes Bester*, Deon
Kruger, and Broadley Miller University of Johannesburg, PO Box 524, Auckland Park, 2006, Johannesburg, South Africa (MATEC Web
of Conferences 120, 2008 (2017) DOI: 10.1051/matecconf/20171200 ,ASCMCES-17)
 Strength and Durability Evaluation of Recycled Aggregate Concrete by:
 Sherif Yehia*, Kareem Helal, Anaam Abusharkh, Amani Zaher, and Hiba Istaitiyeh (Received October 9, 2014, Accepted April 6, 2015,
Published online May 14, 2015)
 http//www.wikepedia.com , the free Encyclopedia

15. Annexures
Crushing process of recycled aggregates Recycled aggregates used to make concrete blocks
And used for land fills
Recycled concrete aggregates
Were used to make these blocks
Concrete blocks made from recycled aggregates