Experimental study on the deterioration of concrete with age on the different buildings in Kampala, Uganda

Abstract

The deterioration of concrete with age in buildings is a common issue at forefront of many engineering professionals. This may be in form of cracking of the structural members, spalling and corrosion of reinforcement among others. Concrete structures are vulnerable to attack both from physical and chemical deterioration mechanisms in form of structural deficiency, plastic settlement, reinforcement corrosion, creep, chemical attack and rapid early evaporation. All these have a negative impact on the concrete structural strength, versatility and durability. It is essential for concrete structures to perform accordingly not only under their specified mechanical requirements but also within their durability specifications. Very often the issue of durability is overlooked since engineers make an assumption that strong concrete is also durable concrete. Many hazardous conditions can rise up as concrete deteriorates in buildings thus rendering them unsafe for occupancy. Proper hardening of concrete plays a very important role in the safety and durability of many concrete structures. The objectives for the study were; to establish the compressive strength of concrete after 7 and 28 days, to determine and compare the current compressive strength of concrete with that at casting on any selected new buildings in Kampala between 0 to15 years and to determine and compare the current compressive strength of concrete with that at casting on any selected old buildings in Kampala between 50 to 100 years. The laboratory test results on the Compressive Strength of the concrete after 7 and 28 days showed a progressive increase as the number of days of curing was increased. The Rebound hammer test results depicted a decrease in the compressive strength as compared to that at casting, indicating a deterioration. The deterioration was more in old buildings between 50 to 100 years with an average compressive strength of 27.33 N/mm2 as compared to that in the new buildings in the range of 0 to 15 years which was 27.38 N/mm2. Thus, old buildings suffer more from concrete deterioration as compared to the new buildings.