Wastepaper sludge ash (WSA) produced from combustion of wastepaper sludge, wood residue, and barks in combusted fluidized bed plant has recently shown potential applications as partial cement replacement in concrete; however, it exhibits expansion at early age. The current results showed the pre-wetting of WSA prior incorporating in concrete as a technique to reduce this expansion. The results conducted on mortar and concrete mixtures containing 20% pre-wetted WSA as cement replacement showed that the pre-wetting helps generating the expected disruptive hydration products before concrete setting, hence reducing the associated expansion problems and improved the strength. The current research also investigated the possibility of reducing the autogenous shrinkage of HPC by using the WSA without any treatments as well as pellets made from the WSA with particle sizes from 1-20 mm. The natural sand was replaced by 1-5 mm pellets and coarse aggregate by 5-20 mm pallets at rates up to 40% in addition to various combinations. The results showed higher early expansion and consequently reduction in the net deformation resulted from the autogenous shrinkage when replacing the natural sand and aggregate by WSA pellets. The drying shrinkage was also reduced especially with the 1-5 mm pellets.
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