Effects of thermal treatment on the characteristics of pulp mill residue

In this study, the effects of thermal treatment at moderately low temperatures (Tmax: 525 °C) on the composition and properties of two distinct green liquor dregs (GLD) samples from two different pulp mills were investigated. This in-depth characterization was conducted with the aim of enabling the use of GLD as raw materials in cementitious applications (e.g., alkali-activated binders). The elemental composition of the GLD samples primarily comprised Ca, Mg, S, Na, and Mn. Analysis using x-ray diffractometry, an electron probe microanalyzer, and scanning electron microscopy revealed that calcite was the main crystalline phase, whereas layered double hydroxides with varying compositions constituted the primary amorphous phase. Characterization through Fourier-transform infrared spectroscopy and thermogravimetric analysis coupled with mass spectrometer analysis, indicated the loss of water and carbon during thermal treatment. Total organic carbon analysis showed that most of the removed carbon was organic, despite some remaining after thermal treatment at 525 °C. A leaching test was conducted to quantify the soluble Ca, Mg, Na, and K content, as well as pH variations. Overall, the findings suggest that thermal treatment enhances the potential of GLD samples for use in binder materials in the construction sector.

Bibliometric review of visual computing in the construction industry

In the construction area, visuals such as drawings, photos, videos, and 3D models, play a significant role in the design, build and maintenance of a facility, bringing efficiency to generate, transfer, and store information. Advanced visual computing techniques facilitate the understanding of design contents, work plans, and other types of information shared in the construction industry. Automatic visual data collection and analysis provide many possibilities to the construction industry and a large number of works have investigated how visual computing can improve construction management processes and other problems in the construction area. However, a comprehensive literature review is needed. This study uses bibliometric approaches to review the works published to date, and analyses the development of knowledge, significant research results, and trends. The purpose of this study is to help newcomers to this research field understand knowledge structure and formulate research directions, thereby enhancing knowledge development. From this study, it can be concluded that computer vision is a key axis of improvement. Moreover, building information modeling, laser scanning, and other visualization-related techniques are also important in advancing the construction area.