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The present study investigated the performance characteristics of concrete paver block (CPB) mixes with incorporated reclaimed asphalt pavement (RAP) aggregates under different curing regimes, namely, continuous water curing (WC), air curing (AC1 and AC2), intermittent water and air curing (WAC), water spray curing (WSC) and heat curing (HC). Seven CPB mixes were formulated by volumetrically replacing virgin coarse and fine aggregates partially and in combination with coarse RAP, fine RAP, and combined RAP fractions. For better refinement of agglomerated particles present in the RAP and to achieve a dense microstructure, the block specimens were fabricated using a design methodology that included a staged mixing approach and time-controlled compaction simultaneously with a vibratory hammer and table vibrator. Hardened CPB specimens were tested to assess mechanical (compressive, flexural, and tensile splitting strength) and durability (water absorption, porosity, and carbonation) properties of the concrete. CPBs fabricated from the considered RAP-inclusive concrete mixes manifested great potential to be used for pavement applications having medium to very heavy traffic when cured with the WC, WAC, WSC, and AC2 curing regimes. Curing regimes WAC and WSC, which involved a combination of water and air curing, were found to be the most effective for the RAP CPB mixes, resulting in superior strength properties. The presence of carbonation was detected in all the RAP CPB mixes when exposed to air curing (AC2) for a prolonged period of time. [ABSTRACT FROM AUTHOR]

Although roller-compacted concrete pavement (RCCP) has been considered the most popular among its counterparts, it has not been widely used due to a number of reasons. The most dominant reason is the variability in mixture proportioning methods and material selection considering its unique behavior compared to conventional concrete mixes. Therefore, the present paper focuses on the above-mentioned parameters by critically reviewing the literature over the past four decades (1984–2021). Initially, the influence of conventional and recycled waste materials on the fresh & hardened state behavior of RCCP is reviewed in detail. Subsequently, the potential applications of various mineral & chemical admixtures and the different types of synthetic and metallic fibers for performance improvement are discussed. In addition, this study has critically appraised various mixture proportioning methods ranging from conventional concrete approaches to empirical, semi-empirical, and theoretical methods for RCCP. The study concludes by noting that all considered materials (alternative aggregates, chemical & mineral admixtures, and fibers) could be used to produce high-quality RCCP; however, an optimal proportion must be prudently selected. Consequently, RCCP could be effectively proportioned by adopting solid suspension, optimal paste volume, and gyratory compaction methods. In addition, it is observed that the strength of the RCCP is related to the aggregate-cement ratio (A/C), water-cement ratio (W/C), and coarse-sand ratio (C/S); the A/C ratio shows an inverse relationship with strength, whereas a mixed behavior between W/C and strength was found. Nevertheless, RCCPs having a vebe time, A/C ratio, and C/S ratio in the ranges of 30–50 s , 5–8 , and 1–1.4 , respectively, could be used for the surface course application of pavements. [ABSTRACT FROM AUTHOR]

This study discusses the effect of utilizing coarse reclaimed asphalt pavement (RAP) aggregates as a replacement to natural coarse aggregates (NCAs) for the production of pervious concrete pavement (PCP) mixes. Coarse RAP (RC) aggregates were utilized in proportions of 0%, 25%, 50%, 75%, and 100%, respectively. It was observed that the porosity and permeability coefficient of the PCP mixes increases considerably as the RAP replacement level increases. Meanwhile, the incorporation of RC was also found to negatively affect the mechanical properties of the PCP mixes. However, the compressive and flexural strength values were noted to be well within the prescribed limits (5–25 MPa and 1–3.2 MPa) required for a PCP mixture. On the other hand, the incorporation of RC was observed to reduce the hardened density, resistance to abrasion, and resistance against aggressive environment of chlorides and sulfates. Therefore, in order to prepare a PCP mixture such that there exists a fine balance in various properties, it is recommended that RC up to 50% may be utilized as a replacement to NCA. In view of achieving maximum sustainability, RC up to 100% may be completely utilized for the production of PCP mixes provided a binary gradation is adopted. Utilization of RAP in preparation of pervious concrete pavement mix will not only resolve the issues related to clearance of an enormous amount of RAP dumps, but would go a long way in dealing with various other environmental and ecological impacts. [ABSTRACT FROM AUTHOR]