Term 4 Exemplar exam memorandum Learner’s Book pages 154 Question 1


1.1 Concrete is strengthened and reinforced using steel and wire to add tensile strength of the material. Concrete can also be reinforced by using different aggregate (chemically inert materials) in the mix. Typically inert materials such as sand, grit or stone are used in different proportions for different strengths of concrete.


1.2 brittle


1.3 Cantilever bridges can only be a certain limited length; they have to have very stable foundations driven or set into stable bedrock; they are difficult to build; sheer stresses at ‘hinges’ or turning points can be extreme for dynamic loads; uneven loading can cause additional stress on joints and hinges


1.4


(2) (1)


(2)


(5) [10]


Question 2 2.1 MA = 


=  


= 3


2.2 High strength to weight ratio to reduce wear and tear; low expansion rate of material at operational temperature; inert material that will not oxidise (rust) or be chemically affected by lubricants; can be manufactured quickly and easily; not too expensive to replace


131 (4) 


(3)


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