Drying shrinkage of alkali-activated slag concrete with natural/recycled aggregates

Each year a large amount of construction and demolition waste (CDW) is generated in the European Union. For sustainability development the CDW is recycled and re-used. To promote the use of CDW, recycled aggregates from CDW were incorporated in alkali-activated concrete (AAC), which mainly consisted of secondary materials or industrial by...

Mitigating the autogenous shrinkage of alkali-activated slag by internal curing

Alkali activated slag (AAS) has shown promising potential to replace ordinary Portland cement as a binder material. Synthesized from industrial by-products, AAS can show high strength, thermal resistance and good durability. However, AAS has been reported to exhibit high autogenous shrinkage. Autogenous shrinkage is a critical issue for building...

Influence of the Ms-modulus on the early-age volume change and heat release of slag and fly ash pastes activated by sodium hydroxide and sodium silicate

Blended pastes composed of slag and fly ash (ratio 50:50) are used with sodium hydroxide and sodium silicate as precursors. Each composition has the same solution to binder ratio (S/B) and the Ms-modulus varies between 1.04 and 1.58. All the experiments were conducted at a constant temperature of 20°C. The physical mechanisms related to the...

Prediction of the chemical shrinkage of Portland cement

Chemical shrinkage is one of the main reasons leading to the early age deformation of concrete. Hence, the prediction of chemical shrinkage is an important issue for evaluating the deformation of concrete and its influence on the durability of concrete structures. There is still room to improve the accuracy for predicting the chemical shrinkage...

Effect of ultra-fine fly ash on the mechanical and shrinkage properties of ultra-high performance concrete

This paper reports on a study to determine the possibility of using ultra-fine fly ash (UFA) for partial or total replacement of normal fly ash (NFA) in ultra-high performance concrete (UHPC). Workability, microstructure, porosity, drying shrinkage as well as mechanical properties were comprehensively studied to investigate the influence of UFA...

The effect of sulfate-rich sewage sludge ash on the volume deformation and micorstructure of cement paste

Sewage sludge ash (SSA) is the combustion residue of the sewage sludge obtained from wastewater treatment plants. In China, SSA normally contains high content of SO3, which may cause detrimental effect on the volume stability of cement-based materials. This study investigated the effect of sulfate-rich SSA (SR-SSA) on the volume deformation and...