Let's evaluate the given options to determine which statement about admixtures is incorrect:

1. Admixtures accelerate hydration:

   Admixtures, in general, do not accelerate hydration unless they are specifically designed as accelerating agents. Accelerating admixtures increase the rate of hydration and the strength gain of concrete, often used in cold weather concrete applications. However, not all admixtures are accelerators. Therefore, this statement, when taken generally, is incorrect, given the context that not all admixtures have this function.

2. Admixtures make concrete waterproof:

   There are specific admixtures known as waterproofing agents that indeed help in making concrete water-resistant by reducing the permeability of concrete. Therefore, this statement is considered correct.

3. Admixtures make concrete acid proof:

   Certain admixtures can improve the acid resistance of concrete by altering the chemical composition or by providing a protective coating. While not all admixtures perform this function, the statement is correct when considering specialized admixtures.

4. Admixtures give high strength:

   Some admixtures enhance the mechanical properties of concrete, including its compressive strength. These are known as high-range water reducers or superplasticizers. They help in achieving high strength in concrete mixes. Thus, this statement is correct.

Based on the above evaluations, the incorrect statement is:

Admixtures accelerate hydration