Improving freeze-thaw resistance of alkali-activated slag by admixtures

Alkali-activated material (AAM) is one of the most attractive alternatives to ordinary Portland cement (OPC). Recently, more and more research interests are devoted to durability performance. In cold areas, freeze-thaw resistance is a crucial durability factor for concrete. However, the understanding of the freeze-thaw resistance of AAMs is...

Can superabsorbent polymers be used as rheology modifiers for cementitious materials in the context of 3D concrete printing?

Autogenous shrinkage may be a critical issue concerning the use of limestone-calcined clay-cement (LC3) in high-performance concrete and 3D printable cementitious materials, which have relatively low water to binder (W/B) ratio. Adding an internal curing agent, i.e., superabsorbent polymer (SAP), could be a viable solution in this context....

Effect of superabsorbent polymer introduction on properties of alkali-activated slag mortar

Internal curing by superabsorbent polymer (SAP) has been applied in alkali-activated slag (AAS) systems by a few previous studies with the purpose to mitigate the autogenous shrinkage. However, the effects of SAP on other properties of AAS have been rarely studied. In this paper, the workability, strength, permeability, and frost resistance...

Influence of liquid-binder ratio on the performance of alkali-activated slag mortar with superabsorbent polymer

The influences of liquid-binder ratio and mixing sequence on the performance of superabsorbent polymer (SAP)-containing alkali-activated slag (AAS) mortar are investigated in this study. It is found that the SAP absorbs much less liquid in upper supernatant of AAS than in water. Mixing SAP with liquid first induces a larger absorption...

Modelling compressive behaviour of cement paste with superabsorbent polymer

Superabsorbent polymer (SAP) can modify the microstructure and influence the mechanical properties of cement paste in at least two ways: while cavities left by SAP increase the total porosity, water released by SAP affects the hydration degree of the surrounding paste. As a starting point for investigation into the overall effect, this study...

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...

Effects of the pre-absorption of superabsorbent polymers and the water-cement ratio of paste on the adsorption-desorption of superabsorbent polymers: an NMR study

As an internal curing material, superabsorbent polymers (SAPs) can effectively reduce the risk of volume shrinkage of cement-based materials. By preparing the cement paste mixed with SAPs, the amount of pre-absorbed water and the water-cement ratio of paste on the water absorption-release behavior in the fresh cement paste were studied by using...

The effect of SAP and SCM on microstructure development in early age fibre reinforced mortars

The use of Supplementary Cementitious Materials (SCMs) in concrete manufacture has significantly increased in the last decades mainly due to their sustainability benefits. Polymeric Fibres (PF) are commonly used in concrete in order to enhance adhesive and frictional bond with a cementitious matrix and improve mechanical properties. Despite...

Analysis of the durability of high strength concrete with superabsorvent polymer

The High Strength Concretes (HSC) provided significant advances in civil construction, due its superior strength, efficiency and durability. Due to the high content of cement, low water/cement ratio and mineral additions, it is essential to avoid the emergence of tensile stresses generated autogenous shrinkage and consequently the cracking of...

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...

Internal curing by superabsorbent polymers in alkali-activated slag

In this study, internal curing by superabsorbent polymers (SAP) is utilized to mitigate self-desiccation and autogenous shrinkage of alkali-activated slag (AAS) pastes. Absorption and desorption kinetics of SAP incorporated in AAS pastes were studied with X-ray tomography. Internal curing delayed the peak of the rate of heat liberation but...

Numerical investigation of crack self-sealing in cement-based composites with superabsorbent polymers

Recently the concept of crack self-sealing has been investigated as a method to prevent degradation and/or loss of functionality of cracked concrete elements. To obtain self-sealing effect in the crack, water swelling admixtures such as superabsorbent polymers (SAP) are added into the cementitious mix. In order to design such self-sealing...

Superabsorbent polymer additives for repeated barrier restoration of damaged powder coatings under wet-dry cycles: A proof-of-concept

Superabsorbent polymers (SAPs) are well known for their ability to absorb and hold high water amounts accompanied by a high volume expansion. In this work we show the benefits of this underlying property of SAPs to induce underwater crack closure with subsequent barrier restoration in damaged protective coatings. For the proof of concept,...

Microfibres and hydrogels to promote autogenous healing in cementitious materials

Cementitious materials are sensitive to crack formation and it would be beneficial if the material could stop the crack propagation, repair the damage and reach again the original liquid-tightness and/or strength. Therefore, a cementitious material with synthetic microfibres and superabsorbent polymers (SAPs) is proposed. Upon crack formation,...