Predicting Concrete Strength

You work in the civil engineering department of a major university. You are part of a project testing the strength of concrete samples. Concrete is the most widely used building material in the world. It is a mix of cement and water with gravel and sand. It can also include other materials like fly ash, blast furnace slag, and additives. The compressive strength of concrete is a function of components and age, so your team is testing different combinations of ingredients at different time intervals. The project leader asked you to find a simple way to estimate strength so that students can predict how a particular sample is expected to perform. Provide your project leader with a formula that estimates the compressive strength. Include: Scoring notes: This is a community-based competition. The top 5 most upvoted entries will win.