The document discusses the problem of building collapses in Nigeria and the effect of temperature on concrete containing clay impurities. It was found that temperature above 400°C causes the compressive strength of concrete with 5% clay addition to drop below the required standard of 21N/mm2. Therefore, the allowable limit of 8% clay impurities may not be valid for concrete exposed to temperatures over 400°C. The study recommends further research on the effect of temperature on other concrete properties and varying percentages of clay addition.

2. BACKGROUND TO THE PROBLEM
• High rate of building collapse in Nigeria has been a source of concern to
Professionals and stake holders in the building construction industry.
• 100% of buildings collapsed in Nigeria were constructed from reinforced
concrete.
• Cement which is the main binder in concrete production is expensive,
thereby increasing the demand to explore pozzolanic potentials of clay
substitute for cement in the local construction industry.
• The Standards Organization of Nigeria (SON) specified that the silt and
clay impurities in sand should not exceed 8%.

3. PROBLEM STATEMENT
• Shabby construction practices such as mixing concrete on the bare
ground adds to the impurities in concrete.
• Clay impurities from different sources have effect on the strength and
physical properties of concrete.
• Subjecting concrete structures to high temperature conditions lead to
uneven expansion of the structure, causes cracks and eventually, failure.
• Hence the need to assess the effect of temperature on concrete
containing clay impurities.

4. AIM OF THE RESEARCH
• To assess by means of literature review and experiment the effect of
varying temperature on the properties of concrete containing clay
addition.
OBJECTIVES
• To investigate the effect of temperature on the compressive strength of
concrete containing 5% clay addition.
• To analyse from data obtained from experiment whether the allowable
8% clay impurities specified by the SON will still be valid if concrete
containing 5% clay addition is subjected to temperature.

5. • What effects do clay impurities have on the properties of concrete?
• What effect does temperature have on the compressive strength of
concrete with 5% clay addition?
JUSTIFICATION
• In Nigeria, during fire outbreaks, buildings are subjected to high
temperatures for long periods of time due to delay or absence of fire
service units.
• Little research has been done on the impact of temperature on concrete
containing impurities such as clay, silt and organic matter.
SCOPE
• 150x150x150mm Concrete cubes produced with Portland cement,
containing 5% clay addition and cured for only 28 days.
• Cubes were subjected to varying temperatures of 100, 200, 300,400 and
500°C only.
RESEARCH QUESTIONS

6. • The incidence of building collapse have become a major concern in the
development of this nation.
• A recent devastating case of building
failure case is the collapse of a 6-storey
guest house belonging to the SCOAN in
Lagos which occurred on the 12th of
September, 2014 resulting in the death
of 116 persons.
• 100% of buildings collapsed in Nigeria are made of reinforced concrete
(Lekan 2011).
CAUSES OF BUILDING COLLAPSE
FINDINGS FROM LITERATURE.
Natural factors Poor Supervision
Operational Problem Socio-economic behaviours of Nigerians
Low quality concrete.

7. EFFECT OF FIRE ON CONCRETE STRUCTURES
• In the building construction industry, adequate attention has not been
paid to fire as a causative factor responsible for building collapse in
Nigeria (Ayuba, Olagunju & Akande 2012).
• Temperatures up to 95°C have little effect on concrete.
• Above 95°C cement paste undergo shrinkage, aggregates expand,
resulting to overall expansion of concrete and reduction in strength.
CONCRETE AS A BUILDING MATERIAL
• A relatively new material and now the most widely used building and
civil Engineering construction material.
• Constitutes of Cement, fine aggregate, coarse aggregate and water.
ADVANTAGES OF CONCRETE
Low Cost Durability Thermal Insulation
Strength Fire resistance
FINDINGS FROM LITERATURE.

8. ADMIXTURES IN CONCRETE
• Admixture are materials added to concrete to modify its properties.
WHY USE ADMIXTURES?
• To reduce to cost of concrete.
• To maintain qualities of concrete during the stages of mixing,
transporting, placing and curing in adverse weather conditions.
POZZOLANA
• Pozzolanic materials possess no cementitious properties but will
chemically react to form compounds possessing cementitious properties.
Eg. Calcined clay, metakaolin, silica fume, rice husk ash, fly ash etc.
WHY USE POZZOLANA?
• High demand of cement.
In Nigeria, annual cement consumption is 19.5 million metric tonnes.
Only 9.5 million metric tonnes are produced locally.
FINDINGS FROM LITERATURE.

9. MATERIALS
• Ordinary Portland cement
• Fine Aggregates
• Coarse Aggregates
• Clay
• Water
TESTS CONDUCTED
• Particle size distribution test
• Bulk density test
• Water absorption test
• Workability test
• Density test
• Abrasion resistance test
• Compressive Strength test
MATERIALS AND METHODS.
METHODS
Concrete mixed homogeneously
With 5% clay Addition.
Steel formwork cleaned and
Lubricated.
Concrete cubes poured into moulds
And rammed for compaction.
Curing of cubes for 28 days
Subjecting of samples to varying
Temperatures.

10. • From the workability test results, there is
reduction in the workability of concrete as
the percentage of clay increase.
• The density test results showed reduction
in density of concrete containing 5% clay
as temperature increases.
• Water absorption capacity of concrete
increases with increase clay percentage.
• At temperatures above 200°C,
compressive strength decreases with
increase in temperature.
RESULTS.
0
100
200
300
400
500
600
2300 2350 2400 2450 2500 2550
Temperature(°C)
Density (Kg/m3)
DENSITY OF CONCRETE WITH 5% CLAY
25.33
29.92 28.89
21.92
20.74
0
5
10
15
20
25
30
35
100 200 300 400 500
Compressivestrength(N/mm2) Temperature (°C)
Compressive strength of concrete with 5% clay

11. • At temperatures above 400°C, the compressive strength of concrete
containing 5% clay addition will fail to meet the required 21N/mm2
• Therefore the 8% allowable clay impurities specification by the
standards organization of Nigeria will not stand at temperatures
above 400°C.
CONCLUSION.

12. • Further research should be done on the effect of temperature on
other properties such as tensile strength of concrete containing 5%
clay addition.
• Research should be done on the effect of varying temperature on
sandcrete blocks containing varying percentages of clay addition.
• Further studies should be done on the effect of chemical attack on
the properties of concrete containing varying percentages of clay
addition.
RECOMMENDATION.