Influence of mixing protocol on fresh and hardened properties of self-compacting concrete

• The influence of different types of mixing on fresh and hardened properties of SCC are studied.
• Forced action and free fall type of mixers are employed for this study.
• Influence of time of addition of superplasticizer on fresh and hardened properties are studied.
• Eirich mixer which is a forced action type provided a homogeneous good mix.
• Time of addition of superplasticizer does not contribute for the variation in hardened properties.

Mixing procedure as well as type of mixing highly influence the fresh and hardened properties of self-compacting concrete (SCC) besides other parameters such as mix proportions, water to powder ratio, and mineral and chemical admixtures. This study attempts to investigate the effect of different types of mixing on the properties of SCC for providing a guideline in choosing the appropriate mixer type. Further, the influence of time of addition of superplasticizer on the properties of concrete is also studied. Four different types of mixer such as pan, Eirich, drum, and ribbon mixers are employed. It is found that the compressive strength and horizontal slump of mix obtained through Eirich mixer is higher compared to all other mixes. Further, no significant influence of time of addition of superplasticizer is noticed on hardened properties whereas marginal increase in flow is observed with delayed addition.