A modern incipient trend is being witnessed in the construction industry wherein concrete is pumped which flows through a nozzle connected to a robotic arm in successive layers in order to develop structural load bearing members generally referred as “Additive manufacturing of Concrete(AMOC)” or 3D Printing of Concrete (3DPC). Numerous challenges are being faced by the construction industry for implementation of Additive manufacturing of concrete to a large scale due to the scarcity of information available w.r.t this technology. This technology has opened up new opportunities which requires intensive research to be carried out to ensure that concrete gets pumped through the pipe(pumpability), extrudes through the nozzle (extrudability), retains its shape once this concrete is extruded from the nozzle(buildability). In addition to this, concrete has to be strong enough to withstand loads induced by upper layers without any deformations (shape retentivity). If the challenges related to pumpability, extrudability, buildability and shape retentivity can be addressed in a better manner, this technology of 3D concrete printing can be utilized to construct houses/building components at a rapid rate and bring down the overall construction costs exponentially with optimal usage and minimal wastage of resources. This paper addresses the various challenges which are commonly encountered in the Additive manufacturing of Concrete (AMOC) summarizing the potential solutions to it discussing some of the case studies of projects which have used this technology.

Stone mastic asphalt (SMA) mix amended with sugarcane bagasse fibers (SBFs) as a stabilizer was investigated experimentally in the present study. The SBF content in the combination mix was varied (0, 0.15%, 0.30%, 0.45% and 0.60%) to produce different mixtures. The prepared mixtures were then assessed for different properties, such as the Marshall stability, tensile strength, and draindown, which are crucial for the performance of the mix in flexible/bituminous pavements. The experimental results revealed enhanced stability and flow value, greater filling of voids in the bitumen, and reduced air voids in the prepared SMA mix amended with SBF. In addition, improvement in the tensile strength of the SMA mix amended with SBF was observed. An increase in the tensile strength ratio of the amended SMA mix was also observed. The susceptibility to the entry of moisture into the pores of the SMA mix was assessed by performing the draindown test, which revealed that the amended SMA mix exhibited reduced draindown due to the presence of SBF. Therefore, it was inferred that the inclusion of SBF into the SMA mix was beneficial for enhancing the stability and tensile strength of the mix and achieving higher resistance to moisture penetration. The present study demonstrated that the use of sugarcane bagasse as an active ingredient in the SMA mix would result in improved performance of flexible pavements while also reducing the waste burden of landfills and aiding in effective waste management.