Final answer:
The slump test and the compressive strength test are two basic tests to check the quality of concrete on-site; the former measures workability while the latter checks load-bearing capacity.
Step-by-step explanation:
Two simple tests used to ensure the quality of concrete delivered on-site are the slump test and the compressive strength test. The slump test measures the consistency and workability of concrete, which is crucial for the ease of handling and proper placement. It involves filling a cone-shaped mold with concrete, lifting the mold, and measuring how much the concrete 'slumps' or falls. The compressive strength test, on the other hand, is conducted by curing concrete samples in a controlled environment and then applying pressure until they break. This test ensures the concrete can withstand the loads it was designed for and determines if it has reached adequate strength before constructing.