Effect of partially hydrated cementitious materials on early-age shrinkage of ultra-high-performance concrete

Abstract

The effect of adding partially hydrated cementitious materials (PHCM) on the early-age shrinkage of ultra-highperformance concrete (UHPC) is investigated. UHPC mixtures incorporating a shrinkage-reducing admixture (SRA) are also tested for comparison. Combined effects of PHCM and SRA in reducing early-age shrinkage are explored. Results indicate a significant improvement in the early-age compressive strength of UHPC mixtures due to PHCM addition.SRA was effective in reducing shrinkage; however, PHCM achieved excellent early-age shrinkage reduction when used alone or combined with SRA. PHCM mitigates undesirable behaviour induced by SRA, including setting time delays and reduction in mechanical properties. The addition of PHCM provides an ecological and economic technique for producing precast and cast-in-place self-restraining shrinkage concrete. Indeed, unused/returned concrete can be recycled in new mixtures to enhance mechanical strength and resistance to shrinkage, and to mitigate set retardation effects.

Prediction of Autogenous Shrinkage of Concrete Incorporating Super Absorbent Polymer and Waste Materials through Individual and Ensemble Machine Learning Approaches

“…The database required for the prediction of autogenous shrinkage was accumulated from published literature and the NU database, incorporating supplementary cementitious materials and SAP [ 34 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 , 113 , 114 , 115 , 116 , 117 , 118 , 119 , 120 , 121 , 122 , 123 , 124 , 125 , 126 , 127 , 128 , 129 , 130 , 131 , 132 , 133 , 134 , 135 , 136 , 137 , 138 , 139 , 140 , 141 , 142 , 143 , 144 , 145 , 146 , 147 , 148 ] (see Supplementary File S1 ). A total of 1889 data points are extracted on different days ranging from one to twenty-eight days.…”

Mechanical Performance and Microstructure of Ultra‐High‐Performance Concrete Modified by Calcium Sulfoaluminate Cement

“…In order to reduce the autogenous shrinkage of UHPC, additions of expansion agent, shrinkage reducing agent (SRA), and super absorbent polymer (SAP) are often incorporated to replace part of cementitious materials at various proportions [11][12][13]. Among them, expansion agent is one of the most effective additives [13].…”

Recycling fresh concrete waste: A review

“…By doing so, the solid products are used as public filling materials for land reclamation or disposed in landfill. In Method 2, the over‐ordered concrete returned to the plant can be directly blended with next batches as partially hydrated cementitious materials to accelerate the setting and hardening progresses . In Method 3, a new nontoxic additive called superabsorbent polymer has been applied to transform the over‐ordered concrete into a granular material for aggregate substitution in new concrete by mixing, discharging, and curing operations .…”

“…In Method 2, the over-ordered concrete returned to the plant can be directly blended with next batches as partially hydrated cementitious materials to accelerate the setting and hardening progresses. [5][6][7][8] In Method 3, a new nontoxic additive called superabsorbent polymer has been applied to transform the over-ordered concrete into a granular material for aggregate substitution in new concrete by mixing, discharging, and curing operations. 9 In Method 4, a reclaiming system (see Figure 3) is used to separate and recycle aggregates and water from the waste containing partially hydrated cement powder as well as a subfraction of fine sand.…”