Why do we place rebar in concrete? Where is the best place to install it in a 6" slab on grade? Choose all correct answers. O To resist diagonal shear; somewhere near the middle O To reduce cracking; about 2" from the bottom O To give it more compressive strength, 3" from the bottom O To give it more tensile strength, about 2" from the bottomWhat is the correct test method for determining the slump of concrete? O to determine the workability of concrete, ASTM C143 O to determine the consistency of concrete, AASHTO T119 to determine both the consistency and workability of concrete, ASTM C145 O to determine the w/c ratio and other consistent concrete properties, ASTM C142You are pouring a very thin patio slab, 3" thick. What two types of reinforcement are best in this application? O fiber mesh and/or small rebar O welded wire and small rebar O welded wire and post tensioning O fiber mesh and welded wireRebar has high ultimate strength greater than its yield strength. 50 ksi. Why do we not use the ultimate strength for our design. Choose the best answer. if:- To be conservative and use a lower value of the steel strength .:j'j:. Because once the steel has achieved its ultimate strength: it has already been deformed by the external loading if:- It depends on the design engineer. {'3- We often use its tensile strength instead. since the steel is often not in compression. How many steel #4 steel reinforcement bars would we need to withstand 150 kips? Assume the working stress is 30 ksi. Next, if we change the rebar from #4 to #5, how many # 5 bars would we need? About 25- # 4 and about 16 # 5 About 16 - #4 and about 25 # 5 O about 13 # 4 and about 21-#5 O about 21 # 4 and about 13 # 5What can you do to help ensure your concrete mix achieves its ultimate strength? Choose the best answer. O Control the vapor retarder and keep off the slab for 2 months O Provide for a moderate cure with proper temperature at least 7 days O Allow for a slow cure with lower humidity and temperature for at least 28 days ( Ensure humidity remains > 80% and temperature stays > 40F and