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DEPARTMENT OF INFRASTRUCTURE ENGINEERING
ENGR20003 Engineering Materials
Pass and Honours Exam Duration: Two (2) hours Reading Time: 15 minutes This paper has 22 pages Authorised materials: Only approved electronic calculators may be used. Protractor and compass may be used. Instructions to invigilators: Closed book examination All the answers need to be written on this exam paper Students can use scrip books as a draft Instructions to students: All questions should be attempted Sections A, B and C are to be answered on this exam paper. You are allowed to use a scrip book as a draft Marks allocated to each question are as indicated. Total marks for the examination equal 100. Paper to be lodged with Baillieu Library ENGR20003 Engineering Materials Page 2 of 22 Section A Construction Materials A1. Steel Construction A 1.1. Indicate which section is more suitable to be used as a column member and which section is more suitable to be used as a beam member. Justify your answer. Figure 1. Figure 2 (8 mark)
ENGR20003 Engineering Materials Page 3 of 22 A 1.2. a) Draw a beam to column connection that has no eccentricity. b) Does the connection need any stiffener? If Yes explain why we need a stiffener. (8 mark)
(Total marks for QA1 = 16) ENGR20003 Engineering Materials Page 4 of 22 A2. Timber Constructions A2.1. Briefly describe using sketches the difference between plain sawn and quarter sawn timber. Discuss with the aid of sketches the issues associated with using plain sawn timber in construction. (5 Marks)
A2.2. Briefly discuss two advantages of using laminated veneer lumber over sawn timber in construction. (5 Marks) (Total marks for QA2 = 10) A3. Concrete formulation: You have to provide a concrete formulation to your concrete supplier at the mixing plant. The concrete you need to make has the following requirements: - Average compressive strength of 25 MPa after 28 days of curing (CS28), safety precautions included. - Slump at 100 mm At the mixing plant they only have the 3 types of aggregate represented in Figure 4 on the page 7. Data: - The sand has a true density of 2.50 t/m3 and is of good quality - The small coarse aggregates have true density of 2.53 t/m3 , and of pass quality - The larger coarse aggregates have an absolute density of 2.67 t/m3, and of pass quality - The cement available is a general purpose cement (GP) with a density ρ(C)=3.1 t/m3 and a true class (Tc) equal to 45 MPa. Equations: = ′ ( − .) Bolomey, where CS28 =targeted strength, A’ = Aggregate Coefficient, Tc = True class of cement, C=cement amount for 1 m3 and W= water amount for 1m3 V = (C0 - Vc), where V= absolute volume aggregates, Vc =Volume of cement, C0 = compactness Your colleague started to use the Dreux-Gorisse’s method in order to determine the amount of cement and water you need for the formulation and he found 400 kg/m3 of General purpose cement (GP) and a W/C of equal to 0.53. ENGR20003 Engineering Materials Page 6 of 22 A3.1. Redo the calculations again, in order to confirm the amount of cement and the W/C that your colleague found using Table 1, Figure 3 and 4 and the data provided. Show on figure 3 the construction marks you used to obtain the amount of cement. (4 Marks)
Table 1: Aggregate coefficient A’ = Aggregate Coefficient (given by the following table) depending on the quality of the maximum aggregates size. Quality of the aggregates Dimension Dmax of the Aggregates Fines Dmax ≤ 12.5 mm Medium 12.5mm < Dmax ≤ 35mm Big Dmax > 35 mm Excellent 0.55 0.60 0.65 Good 0.45 0.50 0.55 Pass 0.35 0.40 0.45 Figure 3: Chart to determine the cement content ENGR20003 Engineering Materials Page 7 of 22 Your colleague has also drawn the Dreux broken line, which is represented on Figure 4 below. Using your partner’s Dreux broken line and assuming that the compactness coefficient of the concrete equals to 0.840, provide the complete formulation by answering questions A3.2., A3.3. and A3.4. Figure 4. A3.2. Determine the proportion of each aggregate (%) using Figure 4. (4 marks
A3.3. Calculate the total volume of aggregates and deduce the volume of each aggregate. (3 marks)