Assessment of shrinkage and bond behaviour of high performance cement-based composites as a repair mortar

There is a need to develop innovative repair materials which can overcome the challenges of cement-based repair mortars being relatively prone to shrinkage effects. In practice, free shrinkage of repair mortar is often considered as an indicator for potential cracking and delamination of applied repair mortars due to restrained shrinkage...

Characterization of one-part alkali-activated slag with rice straw ash

In this paper, fresh (setting and rheology) and hardened properties (strength and shrinkage) of one-part alkali-activated slag (AAS) with and without rice straw ash (RSA) are comprehensively investigated. The reaction kinetics and microstructure of the mixtures are characterized by a series of experimental techniques. The results reveal that...

Physical properties of wood-based materials for liquid deposition modeling

Purpose: The purpose of this study is to quantify the vertical shrinkage rates and the mechanical strength of three-dimensional (3D) printed parts for a variety of wood-based materials for liquid deposition modeling. Design/methodology/approach: The overall hypothesis was that a well-chosen combination of binders, fibers and fillers could...

The effect of furnace steel slag powder on the performance of cementitious mortar at ambient temperature and after exposure to elevated temperatures

Induction furnace steel slag is a secondary product obtained when molten steel is separated from the impurities in the steel-producing furnaces. Though numerous studies have been published on the mechanical strength of concrete/mortar made with steel slag as fine aggregate, relatively few studies focus on the shrinkage, durability (i.e.,...

Effect of metakaolin on the autogenous shrinkage of alkali-activated slag-fly ash paste

The high autogenous shrinkage of alkali-activated materials made from slag and fly ash is recognised as a major drawback with regard to the use as construction materials. In this study, metakaolin was introduced into the alkali-activated slag-fly ash (AASF) paste to mitigate the autogenous shrinkage. The shrinkage mitigation mechanism of...

Early-age properties of alkali-activated slag and glass wool paste

In this study, glass wool waste was utilized by means of alkali-activation with blast furnace slag. Reaction kinetics, workability, mechanical properties and autogenous shrinkage of alkali-activated slag and glass wool were comprehensively studied. Results indicated an optimal modulus (SiO₂/Na₂O) of the activator related...

Cracking Potential of Alkali-Activated Concrete Induced by Autogenous Shrinkage

Alkali activated concrete (AAC) has not received broader industry acceptance, one reason of which lies in the uncertainties in the durability against shrinkage and potential cracking. Many studies reported that AAC exhibit larger autogenous shrinkage than OPC concrete. However, it is unable to deduce that AAC should show higher cracking...

Mechanisms of autogenous shrinkage of alkali-activated slag and fly ash pastes

This study aims to provide a better understanding of the autogenous shrinkage of slag and fly ash-based alkali-activated materials (AAMs) cured at ambient temperature. The main reaction products in AAMs pastes are C-A-S-H type gel and the reaction rate decreases when slag is partially replaced by fly ash. Due to the chemical shrinkage and the...

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...

Cracking potential of alkali-activated slag and fly ash concrete subjected to restrained autogenous shrinkage

This study aims to investigate the cracking potential of alkali-activated slag (AAS) and alkali-activated slag-fly ash (AASF) concrete subjected to restrained autogenous shrinkage. Temperature Stress Testing Machine (TSTM) is utilized, for the first time, to monitor the stress evolution and to measure the cracking time of alkali-activated...

A low-autogenous-shrinkage alkali-activated slag and fly ash concrete

Alkali-activated slag and fly ash (AASF) materials are emerging as promising alternatives to conventional Portland cement. Despite the superior mechanical properties of AASF materials, they are known to show large autogenous shrinkage, which hinders the wide application of these eco-friendly materials in infrastructure. To mitigate the...

Drying shrinkage of alkali-activated slag and fly ash concrete; A comparative study with ordinary Portland cement concrete

This study investigates the drying shrinkage and the shrinkage-induced stress of alkali-activated blast furnace slag and fly ash concrete (AC) in comparison with ordinary Portland cement concrete (OC). For samples that were dried from 1 day after casting, the drying shrinkage of AC was much higher than that of OC. For samples that were stored...

Mitigating the autogenous shrinkage of alkali-activated slag by metakaolin

This study investigates the effectiveness of metakaolin (MK)in mitigating the autogenous shrinkage of alkali-activated slag (AAS). It is found that the autogenous shrinkage of AAS paste can be reduced by 40% and 50% when replacing 10% and 20% slag with MK, respectively. By providing additional Si and Al, and decreasing the pH of the pore...

Subsidence of organic dredged sediments in an upland deposit in Wormer- en Jisperveld: North Holland, the Netherlands

Land subsidence in low-lying peatlands can be caused by shrinkage and organic matter oxidation. When these areas have networks of ditches and canals for drainage purposes, the sediments that accumulate in the waterways can be used to reverse the process of land subsidence. The objective of this study is to understand how dredged sediments can...

Performance of shcc with bacteria for concrete patch repair

The overall performance of concrete patch repair systems depends on the durability of and compatibility between the concrete substrate and the repair material. This paper investigates the performance of a new type of SHCC material with embedded bacteria as a repair material. The bacteria are a healing agent to enhance the durability of the...

Smeared cracking, plasticity, creep, and thermal loading-a unified approach