JORDAN UNIVERSITY OF SCIENCE & TECHNOLOGY Faculty of Engineering Civil Engineering Department Materials of Construction Laboratory CE326 Final Exam Student Name:…………………………………………………………………………………………. Student Number:…………………………………………………………… Section Number:…………………………………….. Problem (1): state whether each of the following statements is true or false. a. The plunger in Schmidt hammer must always be normal to the concrete surface, but the position of the hammer relative to the vertical not affects the rebound number because of the influence of gravity on the moving mass. b. In UPV test the time taken by the pulse to travel through the concrete is measured by an electrical timing unit, when this time increasing the quality of concrete decrease. c. The measured strains at failure increasingly with the reduction in cross section area of steel bar. d. According to the Jordanian standard the dimension of cubes used for determining compressive strength 150×150×150mm. e. Wood can be mainly used as flexural, compressive, and tensile members. f. When the ratio of coarse aggregate to fine aggregate decreased the workability decreased. g. When the water to cement ratio increased the ultra sonic pulse velocity increased. h. If abrasion resistance (Los angles test) less than 50% its considered to be bad quality of aggregate. i. The average within batches COV should not exceed 5%. k. The average between batches related to personal errors only. Problem (2): Complete the following statements: a. Schmidt hammer is sensitive to the presence of ______________and _______________underneath the plunger so it is necessary to take__________readings. b. In UPV test, measured in your lab, the method used of propagating and receiving ultrasonic pulse is _____________transmission. c. The concrete quality will be classified excellent when pulse velocity in Km/sec is _______________. d. In Brinell hardness test the load is applied for a fixed length of time, usually___________. e. If UPV=3.2 Km/sec classify the quality of concrete: excellent, good, medium, doubtful. f. The failure of hard wood is mainly caused by________________ g. If the contractor asked for a higher strength and higher workability for the concrete mix, you suggest to ___________________and____________________. h. The area underneath the stress-strain diagram of steel reflect_______________ i. The normal consistency of cement paste should be taken within _________________ Problem (3): For mix design if a (C : FA : CA) = (1 : 1.7 : 4) mix by mass has a water/cement ratio of 0.5. Calculate the compacted density in Kg/m³, if the cement content of the concrete is 305 Kg/m³. Problem (4): If the concrete cylinder you prepared at the laboratory was tested in splitting and its splitting strength was 8 MPa, so its failure load P was in KN _______________ Problem (5): In order to determine the hardness number, we subjected a steel plate to a force P in Kg, through a sphere-ended rod. If the indentation measured was found to be 3mm, the HN would be 415, find this load P in Kg.____________ Problem (6): For a certain concrete mix, the following weights of aggregate were used with corresponding specific gravity values as shown, solve a, &b. a. If the unit weight of aggregate blended was measured to be 1500Kg/m³, then the voids ratio for the blend would be: Quality Kg/m³ BSGOD Coarse aggregate 920 2.7 Fine aggregate 500 2.35 Silica sand 210 2.65 b. The volume percentage of aggregate blend per 1m³ of concrete. Problem (7): Assume that the force P needed to fracture the concrete prism tested at the material laboratory, if its flexural strength would be 15 MPa, the needed load P would be in kN_________________. Problem (8): A bar of copper originally 305mm long is pulled in tension with a tensile force of 47kN, if the deformation is entirely elastic, what will be the resultant elongation if E=110GPa, original diameter 14mm, and σy=280MPa. Problem (9): If the loose and compacted density for a coarse aggregate were 1275 and 1800 kg/m³, then the loose volume of 150kg of the same aggregate would be._______________ Problem (10): Assume the HN hardness number was found to be 210, the corresponding tensile strength in MPa equals to:___________________.