Taking advantage of the benefits of cooler weather (and cooler concrete), and effectively managing the downside risks take planning, preparation, and understanding some of concrete’s weird tendencies. Even though cooler weather brings risk of freezing, slower slump-loss and setting, and lower early-age strength, cool weather can also increase later-age strength. One irony is that when the weather is really bad, say from December to early March, everybody knows it’s cold and everybody protects the concrete. The real problem comes in cool fall or spring weather when the concrete is not at risk of freezing, but still gets cold enough to experience low early strength that can delay construction operations or put the structure in jeopardy. Even though our intuition is that early-age drying is worse in the summer, in most parts of the US, rapid surface drying is more of a problem in the winter (which is why more skin-crème and chapstick are sold in January than in July). But even when conditions are too hot, too cold, too wet, or too dry, the weather can change in a heartbeat, so we have to be able to change our mixes and construction methods just as fast. ASCC webinars are free to ASCC members | Non-member fee $35.
