Mechanical Properties of Rammed Earth Stabilized with Local Waste and Recycled Materials

Traditional techniques of construction using natural and locally available materials are nowadays raising the interest of architects and engineers. Clayey soil is widely present in all continents and regions, and where available it is obtained directly from the excavation of foundations, avoiding transportation costs and emissions due to the production of the binder. Moreover, raw earth is recyclable and reusable after the demolition, thanks to the absence of the firing process. The rammed earth technique is based on earth compressed into vertical formworks layer by layer to create a wall. This material owes its strength to the compaction effort and due to its manufacture procedure exhibits layers resembling the geological strata and possessing high architectural value. The hygroscopic properties of rammed earth allow natural control of the indoor humidity, keeping it in the optimal range for human health. Stabilization with lime or cement is the most common procedure to enhance the mechanical and weather resistance at once. This practice compromises the recyclability of the earth and reduces the hygroscopic properties of the material. The use of different natural stabilizers, fibers, and natural polymers by-products of the agriculture and food industry, can offer an alternative that fits the circular economy requirements. The present study analyses the mechanical strength of an Italian earth stabilized with different local waste and recycled materials that do not impair the final recyclability of the rammed earth.

Remediation Efficiency of the In Situ Vitrification Method at an Unidentified-Waste and Groundwater Treatment Site

The subject of this study was the dust collected from an electric arc furnace at an unidentified-waste treatment site in southern Taiwan. The dust underwent an in situ vitrification (ISV) process and was tested using the toxicity characteristic leaching procedure (TCLP), at the end of which the final product was analyzed for its stability and weather resistance. This study then examined the above results to determine whether the ISV process helps to enhance the efficiency and economic benefits of said waste-treatment site. A TCLP test conducted on the dust that had been treated with ISV revealed that concentrations of various heavy metals were not only far below those of the unprocessed sample dust but also fell below the limit stipulated in the TCLP regulation of Taiwan’s Environmental Protection Administration. The results show that after undergoing ISV treatment, heavy metals in the dust were either encapsulated or bound in silicon lattices and thus barely leached from the dust. Analyses using scanning electron microscopy (SEM) and an energy dispersive spectrometry (EDS) indicate that the surface of the dust appeared more compacted after going through the ISV process. In addition, the highly contaminated dust that underwent ISV treatment saw a pronounced decrease in or elimination of wave crests. Another analysis applying X-ray diffraction (XRD) showed that the SiO2 crests disappeared in the processed dust, suggesting that the crystal structure was replaced with quasi-vitreous products after ISV treatment. In the event that pollutants were extant, they were usually characterized by smaller size, high stability, excellent weather resistance, an innocuous nature, and recyclability.

Evaluating the Protective Effects of Calcium Carbonate Coating on Sandstone Cultural Heritage

The purpose of this work was to use different surfactants to deposit different crystalline calcium carbonate films on the surface of sandstone through a simple double displacement reaction. This was done to test the protective effects of calcium carbonate coatings based on water absorption, moisture permeability and weather resistance. Experimental results showed that the air permeability of the stone treated with vaterite calcium carbonate was reduced, but that this did not affect water vapor’s access into and out of the stone. Compared with untreated stone, the water absorption rate was reduced 0.5 times, and the weather resistance increased by 4 times due to small crystal grains, high solubility, and deep penetration hindering the erosion of water and soluble salts. These findings are expected to provide useful suggestions for the protection of stone cultural heritage.

Two Birds with One Stone: Preparation of 4, 4-Diaminodiphenylmethane Functionalized GO@SiO2 with Mechanical Reinforcement and UV Shielding Properties and Its Application in Thermoplastic Polyurethane

This study prepared 4,4-diaminodiphenylmethane (DDM)-functionalized graphene oxide (GO)@silica dioxide (SiO2) nano-composites through amidation reaction and low-temperature precipitation. The resulting modified GO, that was DDM−GO@SiO2. The study found that DDM−GO@SiO2 showed good dispersion and compatibility with thermoplastic polyurethane (TPU) substrates. Compared with pure TPU, the tensile strength of the TPU composites increased by 41% to 94.6 MPa at only 0.5 wt% DDM−GO@SiO2. In addition, even when a small amount of DDM−GO@SiO2 was added, the UV absorption of TPU composites increased significantly, TPU composites can achieve a UV shielding efficiency of 95.21% in the UV-A region. These results show that this type of material holds great promise for the preparation of functional coatings and film materials with high strength and weather resistance.

2D electrical resistivity imaging to determine depth of andesite spreading at Tanjung Batu, Jambi as eco-friendly exploration of minerals method

Tanjung Batu has potential subsurface minerals in the form of Andesite rocks. Andesite can be used appropriately for infrastructure with excellent physical features, including hardness, compressive strength, density, as well as the water and weather resistance level. Andesite is one type of igneous rock that is widely used in the construction sector, especially infrastructure such as roads, bridges, housing, airports, and seaports. In mining, the depth of mineral exploration usually using borehole method. In this study used electrical resistivity method with dipole-dipole configurations. Electrical resistivity is also capable for identifying Andesite rocks in subsurface without drilling the area because each rock has a different rock resistivity value. In this study used 240 meters of track and 20 meters space of electrodes. Based on 2D Imaging, range of Andesite resistivity in this area was 170 - >1095 Ωm. Andesite depth was at 3.42, 10.6, 18.5 and - 27.2 m.

Evaluating The Protective Effect of Calcium Carbonate Coating On Sandstone Cultural Heritage

The purpose of this work is to use different surfactants to deposit different crystal forms of calcium carbonate film on the surface of sandstone through a simple double replacement reaction. The protective effect of calcium carbonate coatings was evaluated through water absorption, water vapor permeability and weather resistance tests. The results show that the stone treated with vaterite calcium carbonate has excellent water absorption and permeability. Compared with untreated stone, the water absorption rate is reduced by 0.5 times, and the weather resistance is increased by 4 times, effectively hindering the erosion of water and soluble salts. These findings are expected to provide useful suggestions for the protection of stone cultural heritage.

Mechanical performance of aluminum reinforced wood plastic composites under axial tension: an experimental and numerical investigation

Wood plastic composites (WPCs) are low-cost biomass composite materials with good mechanical stability and good weather resistance that are mainly used in the areas with low stress levels. Aimed at improving the mechanical properties of WPCs, this paper proposes a new WPC reinforced with aluminum. The WPC and aluminum were hot pressed to form an aluminum reinforced wood plastic composites (A-WPC). The axial tensile properties, stress–strain relationship, and failure mechanism of the composite were studied experimentally. The results show that the ultimate stress and strain, elastic modulus, and other mechanical parameters of A-WPCs are much higher than those of WPCs. The elongation at break is 10.13 times that of WPCs, which greatly improves the ductility. Based on the equivalent stiffness theory, two calculation models were proposed to predict the tensile stress–strain relationship of A-WPCs. The tensile rebound process of A-WPCs was analyzed in depth, and then the calculation formula of the residual curvature was deduced to compare with the test results. The experimental results are in good agreement with the calculation results.