In the United States, concrete strength is measured in "pounds per square inch" or psi. In Europe, concrete strength is usually measured in megapascals, which is abbreviated MPa. Both 32 MPa and 5,000 psi are minimum strengths. 5,000 psi concrete that actually tests at 5,600 psi is not defective. And, 32 MPa converts to 4,643 psi. So the brief answer, without discussing air entrainment or surfactants, is that in the United States you mix widely available 5,000 psi (or 34.5 MPa) cement with the proper amount of fine and course aggregates and water and then you allow that concrete to cure to full strength, which takes about a month.
Step 1
Weigh a 5-gallon plastic bucket on a scale.
Step 2
Weigh out exactly 100 pounds of 5,000 psi cement using the bucket. Subtract the weight of the bucket from the weight of the cement and the bucket to calculate the weight of the cement.
Step 3
Pour the cement into a 4.5 cubic foot portable cement mixer.
Step 4
Measure out 200 pounds of fine sand and 300 pounds of 3/4-inch gravel using the same procedure you used to weigh the cement. Add these fine and course "aggregates" to the cement mixer.
Step 5
Measure out 40 pounds of water in the 5-gallon bucket using the same procedure you used to measure the weight of the other ingredients. Add the water to the mixer. Five gallons of water weighs 41.65 pounds, so you will need to add a little less than 5 gallons.
Step 6
Turn on the mixer and mix all the ingredients for about five minutes. Use the concrete for whatever application is engineered to require a strength of 32 MPa. After curing for 28 days, your concrete should have a compression strength that exceeds 32 MPa.