In RCC work, if the adhesion of the concrete to steel is not perfect within elastic limits, then:
(a) Steel will be overstressed
(b) Steel reinforcement may break
(c) Concrete will be overstressed
(d) Steel will bear more stress than concrete
Answer (2)
In RCC work, imperfect adhesion between concrete and steel leads to uneven load distribution. As a result, the steel reinforcement will bear more stress than the concrete, potentially leading to overstressing and failure. Thus, the correct answer is (d) Steel will bear more stress than concrete.
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In the context of Reinforced Cement Concrete (RCC), the adhesion or bond between concrete and steel reinforcement is crucial for the composite material to perform optimally under loads. This bond ensures that the two materials work together, allowing forces to be distributed effectively between them.
When the adhesion between concrete and steel is not perfect within the elastic limits, it generally results in 'slip' or relative movement between the two materials. Let's consider the options given:
(a) Steel will be overstressed : Without good adhesion, the forces that should be shared between concrete and steel are instead more retained by the steel. However, the stress in steel isn't necessarily higher than intended because the steel is typically designed to handle the majority of tensile stresses anyway.
(b) Steel reinforcement may break : While poor adhesion can eventually lead to failure, it is not commonly the cause of steel breaking directly within elastic limits. Steel's breakage would usually happen if it is subjected to stresses significantly beyond its yield strength.
(c) Concrete will be overstressed : Poor bonding doesn't directly lead to the concrete bearing too much stress by itself, as the adhesion typically affects how the load is shared between the steel and concrete.
(d) Steel will bear more stress than concrete : This option is the most correct. When the bond is weak, steel may end up carrying more than its intended share of the tensile forces compared to the scenario where the bond is intact. However, given that concrete is weak in tension anyway, steel is meant to take on most tensile loads even when bonding is perfect. But, in imperfect bonding conditions, steel takes even more than usual.
Therefore, the most likely answer is:
(d) Steel will bear more stress than concrete.
This problem exemplifies the importance of ensuring a good bond in RCC constructions to prevent unexpected shifts in stress distribution which can lead to premature structural issues.
