A review on the effects of chemical admixtures on Autoclaved Aerated Concrete (AAC) blocks

Autoclaved Aerated Concrete (AAC) is a special composite and widely accepted construction material owing to good durability, raw material availability, and environmentally friendly nature. Nevertheless, the continuing focus of the industry remains in cost optimization and maximizing the performance of blocks. The investigations related to the effects of admixtures in AAC are continuing globally with the objective of improving the productivity and strength improvement of AAC blocks. It is now well documented that the behavior of admixtures in conventional concrete and AAC is different, partly due to the low quantities of cement in a mix design and production systems. Hence it is essential to conduct a detailed investigation for finding the suitability of chemical admixtures. This review paper shows the trend of admixtures used in AAC and describes how they affect the rheological characteristics, setting time, and mechanical properties. From the review, it is clear that the performance of admixtures mainly depends on the type of binder, type, and dosage of admixtures. PCE‐based superplasticizers and performance enhancers are generally recommended to provide incremental improvement in flow behavior and mechanical strength. However, it is important to note the mix design and complex interplay of various materials have a large impact on the performance of any admixture employed. The investigations thus far indicate that chemical admixtures also impact the initial curing times without sacrificing the mechanical properties of AAC. In general, the usage of admixtures can enhance the strength of blocks between 5% and 15% depending on the type and quantity of admixture.