Wyniki wyszukiwania - BazTech

1

Performance studies of premixed blended hydraulic cement to revolutionize concrete production

Lin Kae-Long, Lin Wei-Ting, Fiala Lukáš, Kočí Jan, Lee Po-En, Hsu Hui-Mi

Materials Science Poland

|

2024

|

Vol. 42, No. 3

139--159

EN

In recent years, ready-mix concrete plants have increasingly utilized premixed blended hydraulic cement. These formulations incorporate a higher mineral admixture content than traditional ternary concrete mixtures, resulting in improved durability, compactness, and reduced hydration heat during curing. This study examined four concrete proportions with a water–binder ratio of 0.32, focusing on workability, compression strength, and chloride penetration resistance. The research also considered economic effects and carbon emissions. The findings revealed that premixed blended hydraulic cement improved late strength development and reduced chloride permeability. Additionally, the partial replacement of cement with silica fume enhanced early strength and chloride resistance. However, these benefits came with trade-offs, including adverse effects on workability and increased hydration heat. Notably, a 50% cement mixture in premixed blended hydraulic cement emitted 42–49% less CO2 than conventional formulations, highlighting its potential for reducing environmental impact in concrete production.

2

A brief overview of the use of additive manufacturing of con-create materials in construction

Mierzwiński Dariusz, Łach Michał, Gądek Szymon, Lin Wei-Ting, Hung Tran Doan, Korniejenko Kinga

Acta Innovations

|

2023

|

no. 48

22--37

EN

Currently, additive technology is becoming increasingly popular in different areas, including its applications in construction industry. The main aim of the chapter is to show the selected applications of 3D printing technology in the construction industry and the usage of this technology on distinct stages of a construction project, from architectural design to performance of residential buildings and other civil engineering constructions. The chapter is based on a critical analysis of the literature sources, as well as the authors' experiences. The data collected are supported by selected case studies from five projects. The main findings show that 3D printing brings a lot of advantages in the construction industry, for instance: low labour costs, less waste, and high efficiency, but it still requires development and optimization.

3

Electrical resistance and self-sensing properties of pressure-sensitive materials with graphite filler in Kuralon fiber concrete

Cheng An, Lin Wei-Ting, Fiala Lukáš, Hotěk Petr, Chao Sao-Jeng, Hsu Hui-Mi

Materials Science Poland

|

2022

|

Vol. 40, No. 2

223--239

EN

This study aimed to investigate conductivity behavior of concrete containing graphite and its sensitivity to the effects of pressure. Graphite powder was added to concrete to replace partial cement (4 wt.%, 8 wt.%, 12 wt.%, and 16 wt.%) as conductive fillers with a water-to-cementitious ratio of 0.45. Specimens with 0.5 vol.% Kuralon fibers were treated to enhance the performance of self-sensing properties to investigate the influence of graphite and fiber contents on electrical resistivities. The relationship between the axial load and changes in resistivity was determined using cyclic loading tests, indicating the existence and development of internal cracking in concrete. The results indicated that the compressive strength presented a linear decline proportional to the addition of graphite. Specimens with 8% graphite reached the lower bound of self-sensing properties, and with an increase in the amount of graphite, resistivity gradually decreased. In the cyclic loading tests, specimens containing >8% graphite were able to better reflect the relationship between loading and resistivity. Kuralon fibers in concrete had further improvement in resistance and self-sensing properties. In inclusion, the mixture with 8% graphite provided the best self-sensing properties to warn for preventing the effects of cracking, as well as achieved better mechanical properties.

4

Delayed setting time for alkali-activated slag composites using activator containing SiO2 and Na2O

Hung Chi-Che, Lin Wei-Ting, Yeih Wei-Chung, Chang Jiang-Jhy

Materials Science Poland

|

2021

|

Vol. 39, No. 4

570--579

EN

This study examines the influence of SiO2 and Na2O mix proportions on the properties of alkali-activated slag (AAS) pastes. In order to solve the rapid setting problem associated with AAS, phosphoric or silicic acid is commonly added to the alkaline activator. The retarding effect of these additions suggests a close relationship between pH and setting time. In this study, AAS pastes with various SiO2 and Na2O dosages were analyzed. Regression analysis was carried out using pH value and setting time to identify the main parameters affecting the setting time. Results showed that the alkali modulus (i.e., the weight ratio of SiO2 over Na2O) is correlated with the pH value. Specifically, the initial and final setting times were significantly reduced under lower SiO2 and Na2O dosages. Therefore, a higher alkali modulus prolonged the setting time.

5

A study on the mixed properties of green controlled low strength cementitious

Chen Sung-Ching, Lin Wei-Ting, Lin Kae-Long, Huang Po-Yu

Materials Science Poland

|

2021

|

Vol. 39, No. 1

59--74

EN

In this study, two industrial wastes – circulating fluidized bed combustion co-fired fly ash (CFA) and ground granulated blast-furnace slag (GGBS) – were used as green materials instead of cementitious materials in controllable low strength material (CLSM). CLSM was used to backfill the pavement. CLSM should meet the compressive strength requirements of the CLSM specification (under 8.24 MPa), and it had the self-consolidating characteristics of fluidized concrete. In order to comply with the characteristics of self-consolidation, a mix design including superplasticizers, adhesives, and accelerators were used to ensure that the proportion could meet the requirements of both CLSM and the self-consolidating properties. The test methods included the slump flow test, ball drop test, strength activity index, compressive strength, mercury intrusion porosimetry, chloride migration test, and scanning electron microscope. A water/cement ratio of 0.85 was used as the mix design for the CLSM requirements. The CFA and GGBS used in CLSM could replace 78 wt.% of the cement, and CLSM could effectively meet the requirements of the workability, strength and microscopic properties.