Final answer:
Calcium aluminate cement and Portland cement are the two cements that use chemical bonding for retention, forming a durable bond through a process called hydration.
Step-by-step explanation:
The two cements that use chemical bonding for retention are calcium aluminate cement and Portland cement. These cements create a bond through a chemical reaction that occurs when they are mixed with water, a process known as hydration. This reaction results in the formation of compounds that harden over time, effectively adhering to the aggregates within the concrete and leading to a strong, durable bond.