| dc.description.abstract | Most sanitation structures in the world are constructed using concrete which is reinforced by
the steel metal, this type of concrete is called Reinforced Cement Concrete (RCC). The RCC
structure is believed to be relatively resistant to corrosion which the sanitation structures are
prone to due to the aggressive environment in which they are subjected to. This belief has
been compromised since the reinforced concrete used in the sanitation structures such as the
concrete sewer pipes has become susceptible to Microbiologically Induced Deterioration
(MID). This MID leads to degradation and compromised strength and service life of the
RCC. In the reinforced concrete structure, the backbone of this structure is the reinforcing
steel which when its strength is compromised by the MID, the whole structure is
compromised. The cost of repair of the reinforced concrete structure is very expensive and,
in some cases, repair cannot work hence calling for construction of new structures which is
also expensive. Among the sustainable development goals (SDGs), the SDG number 6
advocates for sanitation as a basic human right, the advocacy is found in the Kenyan 2010
constitution Article 43(1)(b). This therefore means that sanitation structures should be taken
seriously and their constructions should be up to the required standards. Quick and amicable
solutions should be in place to counter anything which may comprise their service lives or
condition of use. This research aimed at analyzing the strength of steel metal used for
reinforcing concrete in sanitation structures. Reinforced concrete specimens were developed
using different types of cement and different concrete cover. The three different types of
cement were, Ordinary Portland Cement (OPC), Portland Pozzolana Cement (PPC) and
Limestone Calcined Clay Cement (LC3), while concrete covers of 15mm and 25mm were
applied. They were then subjected to a aggressive environment (sewage sample) suitable for
corrosion just like in their actual operational environment. To determine the effects of MID
on the steel metal, the steel metal was tested using Universal Testing Machine (UTM) and
Torsion Machine TM for various tests. The three types of strengths: bending, tensile and
torsion before and after being subjected to aggressive environment were determined. The
testing of the specimens was done at an interval of 14 days for a period of three (3) months.
According to the results, LC3 with a concrete cover size of 25 mm showed minimum
percentage reduction in strength compared to PPC and OPC. It had the lowest percentage
reduction in strength after 84 days which was 5.25%, final strength 94.75%, for a concrete
cover size of 25mm. PPC had a reduction of 7.24%, final strength was 92.76% and OPC had
a reduction of 7.20%, final strength was 92.8% for 25mm concrete cover size. Generally,
LC3 showed minimum percentage reduction in strength followed by PPC then OPC for all
the strength tests which were performed. According to these research findings, to realize
better service life for concrete sanitation structures, LC3 cement with a cover size of not less
than 25mm may be applied during their construction. | en_US |
