The use of phosphogypsum to prepare phosphorus building gypsum (PBG) is of great value to the resource utilization of phosphogypsum. In this study, PBG was ball-milled to obtain phosphorus building gypsum with good performance, which can meet the requirements of the Chinese standards for first-class building gypsum. Meanwhile, the changes of net slurry physical properties, mechanical properties, and particle size parameters of PBG under different treatment times were analyzed. With the increase of ball milling time, the particle size of PBG decreased rapidly and then stabilized, and the specific surface area gradually increased and then started to rise back. Ball milling can significantly reduce the standard consistency water requirement of phosphogypsum, resulting in a shorter setting time and higher strength of phosphogypsum. In the fixed water consumption test, the effect of ball milling time on the performance of phosphogypsum was small. Compared with sieving, washing, aging, and other means of PBG treatment, ball milling has the advantages of simplicity, environmental protection, and low cost, and it has some practical significance in production.

Phosphogypsum is an industrial by-product from the wet preparation of phosphoric acid. Phosphorus building gypsum (PBG) can be obtained from phosphogypsum after high-thermal dehydration. Improving the mechanical properties of PBG is of great significance to extending its application range. In this paper, PBG was modified by adding nano-CaCO3. Specifically, this study, conducted on 0.25–2% nano-CaCO3-doped PBG, tested effects on the fluidity, setting time, absolute dry flexural strength, absolute dry compressive strength, water absorption and softening coefficient of PBG, followed by its microscopic analysis with SEM and XRD. The experimental results showed that, with an increase in nano-CaCO3 content, the fluidity and setting time of PBG-based mixes were decreased. When the content was 2%, the fluidity was 120 mm, which was 33% lower than that of the blank group; the initial setting time was 485 s, which was 38% lower than that in the blank group; the final setting time was 1321 s, which was reduced by 29%. Nano-CaCO3 evidently improved the absolute dry flexural strength, absolute dry compressive strength, water absorption and softening coefficient of PBG to a certain extent. When the content was 1%, the strengthening effect reached the optimum, with the absolute dry flexural strength and absolute dry compressive strength being increased to 8.1 MPa and 20.5 MPa, respectively, which were 50% and 24% higher than those of the blank group; when the content was 1.5%, the water absorption was 0.22, which was 33% lower than that of the blank group; when the content approached 0.75%, the softening coefficient reached the peak of 0.63, which was 66% higher than that of the blank group. Doping with nano-CaCO3 could significantly improve the performance of PBG, which provides a new scheme for its modification.

The Southwest provinces of China are locations with a rich variety of different dwelling design typologies based on traditional cultures and ethnic groups. In this area, the Province of Yunnan has many such dwelling types, and it is also an area with most frequent earthquakes in China. The seismic problems of housing structure must therefore be solved as part of the study on sustainable development of villages to provide relevant advice for future design options. This paper reports research, which evolved over a ten-year period that deals with the seismic capacity of residential buildings. Simulations using shaking table tests were carried out to assess the performance of traditional residential structures as well with the impacts of material modifications and the structural strengthening of common residential building components found in Yunnan. Relevant and pertinent construction technology solutions that could enhance the seismic capacity of residential buildings and act as innovative improvements for the sustainability of rural dwellings are suggested.

This paper introduces the impact experiment and an engineering application of the new composited wall which composed of calcium silicate composited board. Clearly defines the impact resistance of the wall in different connection as interior walls and exterior walls through observing the wall’s changes in the number of 5 times or even up to 50 times impact (10 times of the national standard). It can be known from the experiment that long wall has large vibration but good integrity. The window wall may fracture easily and is not able to meet the minimum standard requirements of impact resistance when the width is small. It needs to take reinforce measures.