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Research on the combined substitution of supplementary cementitious materials (SCMs) has already demonstrated that it might be one of the few viable options to produce low-carbon concrete at scale. This paper presents an experimental investigation on the performance and durability of rice husk ash (RHA) and calcined clay (CC) in ternary blended concrete exposed to chloride attacks under wet/dry cycles. Portland cement (PC) was replaced by RHA and CC up to 50% by weight to produce low-carbon concrete. Samples were subjected to wet/dry cycles in 3.5% NaCl water, with mineralogical composition and microstructure development before and after exposure analysed by TGA-DSC, MIP, XRD, and SEM. The durability of the concrete against wet/dry cycles was investigated in terms of compressive strength, water absorption, open porosity, density, thermal conductivity, and electrical resistivity. The results showed that concrete mixes with CC and RHA up to 60% exhibited an increase of 33% in compressive strength, followed by minimal changes in water absorption. While a decrease in electrical resistivity was measured in all samples with RHA and CC, increasing the CC content to 50% resulted in improved resistance to chloride penetration. Increasing the CC content resulted in a more refined microstructure, with an overall decrease in porosity of up to 32% compared to the control series. While RHA alone did not contribute to significant improvements after wet/dry cycles, the combined substitution of RHA and CC at SCM replacement levels of 60% showed an overall improvement in hardened properties and durability. This investigation provides valuable insights into the long-term performance and strength of innovative low-carbon concrete. [ABSTRACT FROM AUTHOR]

Nanomaterials have emerged as a future application to concrete technology due to their unique composition. This study presents a review of nano CaCO3 in terms of microstructure, rate of hydration, consistency, flowability, setting time, workability, compressive strength, sorptivity, chloride resistance, and corrosion resistance. A remarkable decrease in pores and chloride ion penetration can be observed from the study. Compared to the controlled concrete, the addition of 1% nano CaCO3 also resulted in the reduction of the chloride diffusion coefficient. Compressive strength showed a significant improvement with the inclusion of 1-2% nano CaCO3, however, increasing its quantity showed reduction in compressive strength property. The accelerated hydration reaction forming supplementary C-S-H gel observed in the concrete containing nano CaCO3 has remarkably improved the microstructure of the mix by reducing its porosity. This study is an initiative to accumulate findings of nano-materials for its broad acceptance and future scope of work. [ABSTRACT FROM AUTHOR]

Self‐compacting concrete (SCC) was developed in 1988 and introduced by Professor H. Okamura to achieve durability of structures with low skilled laborers. The three properties of SCC that differentiates it from traditional concrete are passing ability, filling ability and segregation resistance. The present study highlights the developments concerning SCC in the period from 1995 to 2017. This information is important for researchers and professionals working in this area. SCC can be optimized to a larger extent to find the best alternative either by use of additives or tailor‐made mix design. Based on different principles and parameters, design methods can be categorized into six classes namely empirical design method, statistical factorial design method, strength‐based design method, rheology of paste method, particle packing method and Eco‐SCC mixture design method. To develop SCC with high quality a suitable method can be chosen depending upon the situation and application. [ABSTRACT FROM AUTHOR]