Effects of experimental ternary cements on fresh and hardened properties of self-compacting concretes

摘要

Self-compacting concrete (SCC) is a concrete that flows alone under its dead weight and consolidates itself without any additional compaction and without segregation. As an integral part of a SCC, self-compacting mortars (SCMs) may serve as a basis for the mix design of concrete since the measurement of the rheological and viscosity properties of SCC is often impractical due to the need for complex equipment. This paper discusses the properties of SCM and SCC with mineral additions. ordinary Portland cement (OPC), natural pozzolana (PZ), and marble powder (MP) are used in ternary cementitious blends system following the cement substitution with PZ and MP in ratio 1/3. Within the framework of this experimental study, a total of 12 SCM and 6 SCC were prepared having a constant w/b ratio of 0.40. The fresh properties of the SCM were tested for mini-slump flow diameter, mini-V-funnel flow time, and viscosity measurement. Slumps flow test, L-box, J-ring, V-funnel flow time, and sieve stability were measured for SCC. Moreover, the development in the compressive strength was determined at 3, 7, 28, 56, and 90days. Test results have shown that using ternary blends improved the fresh properties of the mixtures. The combination of natural pozzolana and marble powder increase the slump flow test up to 826 mm for the mixture prepared with 10% of mineral additions. Moreover, the use of mineral addition reduced the time flow to 4.27s for SCC with 20% mineral addition, thus reducing the viscosity of all mixtures. Addition of MP increases the capacity of the passage through the plates between 88.75 and 93.50% for SCC with 7.5 and 15% of MP, respectively. The ternary system (PZ and MP) improve the sieve stability with the value for 4.07% of SCC with 50% of substitution compared for SSC without additions. The compressive strength of SCC at 90days with 40% of PZ and MP was similar to that of OPC.