Title: The Use of Crushed Limestone Dust in Production of Self-Consolidating Concrete (SCC)
Author(s): C. Shi, Y. Wu, and C. Riefler
Publication: Symposium Paper
Appears on pages(s): 115-130
Keywords: autogenous shrinkage; coal fly ash; drying shrinkage; flowability; limestone dust; segregation; self-consolidating concrete; strength
Crushed limestone dust is a waste material from the production of concrete aggregate by crushing quarried limestone rocks. The dust is usually less tan 1% of the aggregate production. Although it is coarser than common cementing materials such as as Portland cement, coal fly ash and ground blast furnace slag, it is fine enough to cause many problems during materials handling and disposal. Laboratory results have indicated that crushed limestone dust can be used to produce self-consolidating concrete (SCC) with properties similar to those of SCC containing coal fly ash. . Due to the differences in morphologies and particle size distribution, the mix design has to be modified when crushed stone dust instead of fly ash or ground blast furnace slag is used. Fresh SCC mixtures containing limestone dust loses its flowability and sets faster than the mixtures containing fly ash due to the acceleration of the hydration of Portland cement by the limestone powder. SCC containing limestone dust exhibited strengths similar to that containing fly ash during the first seven days, but the former exhibited lower strength than the latter at 28 and 90 days due to the contributions from the pozzolanic reactions between coal fly ash and lime released from the hydration of Portland cement. The former also have lower autogenous and drying shrinkages than the latter.