جستجوی مقالات مرتبط با کلیدواژه "calcium carbide residue" در نشریات گروه "عمران"

The present research was conducted with the aim of investigating the effect of the type of filler on the mechanical properties of the stone mastic asphalt (SMA). For this purpose, five types of fillers, including silica filler (SF) as the base filler in the control sample, Portland cement (OPC) and limestone powder (LSP) as common fillers, and recycled glass powder (RGP) and calcium carbide waste (CCR) as recycled fillers, were used in their pure form or combined with each other. In order to investigate the resistance of the samples against rutting, the Marshall test was used to obtain the Marshall strength (MS) and especially the Marshall coefficient (MQ). Also, resistance to cracking and moisture sensitivity were also evaluated by performing the Indirect Tensile Strength (ITS) test in dry and saturated conditions and obtaining the Tensile Strength Ratio (TSR). The results have shown that the samples containing recycled fillers had the best performance in improving the properties of SMA asphalt. such that the use of the combination of recycled fillers, in addition to improving the properties of SMA compared to samples containing silica fillers, The values of MS, MQ, ITS, and TSR have increased by 36, 19, 24, and 31%, respectively, compared to the best results obtained using common fillers. Therefore, the use of RGP and CCR compounds as fillers in SMA asphalt, in addition to helping to protect the environment, natural resources and economic savings, can also be technically very effective in improving the service life of asphalt mixtures.

Stabilizing weak and poorly graded soils in engineering projects is commonly achieved using lime and cement. However, the cement production process requires significant energy and generates a substantial volume of carbon dioxide, which presents considerable environmental risks. As an alternative to cement and lime, alkali-activated aluminosilicates have gained recognition due to their cost-effectiveness and environmental compatibility. This study aims to investigate the feasibility of utilizing metakaolin as a stabilizing agent for sandy soil, with Calcium carbide residue (CCR) serving as an alkaline activator. To this end, factors such as the concentration of alkaline activator, metakaolin content, curing time, and temperature of treated soil samples were examined through unconfined compressive strength (UCS) and California Bearing Ratio (CBR) tests. The results were then compared to those of sand stabilized with Portland cement. Furthermore, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were used to analyze the microstructures formed during the soil stabilization process. The findings indicate a significant increase in the stabilized soil samples' compressive strength and ductile behavior. Moreover, the analysis of the developed microstructures in the stabilized soil samples demonstrates a noticeable bond between the binding gel and sand particles and the filling of intergranular space with alkali-activated binding gel. Overall, the findings of the present study suggest that the introduced binding gel has the potential to be an environmentally compatible stabilizing agent for stabilizing sandy soils.

Nowadays, the ordinary Portland cement (OPC) industry causes to extensive environmental consequences due to consuming huge amounts of fossil fuels. This necessitated researchers to introduce a novel group of binders called “Geopolymer cements” or “Green cements” with higher performance and lower pollution compared to the OPC. Thus, in this research, the effect of using two types of alkaline activators such as sodium hydroxide (NaOH) and calcium carbide residue (CCR), for stabilization of clay soil (CL) has been investigated. Initially, the chemical compositions of soil, recycled glass powder, calcium carbide residue, and sodium hydroxide were obtained via X-ray fluorescence (XRF) test. Then, the mechanical behavior of different unstabilized, geopolymer-stabilized, and OPC-stabilized samples has studied using unconfined compressive strength (UCS) test. The effects of several parameters such as the type and concentration of alkaline activators, the curing times (7, 28, and 91 days), and the initial synthesis temperature (25 and 70 ˚C) on the UCS and failure strain of samples have been assessed. Moreover, in order to studying the microstructure of samples, the scanning electron microscope (SEM) images and energy dispersive X-ray (EDX) analysis of selected samples have been used. Results showed the effective stabilization of soil geopolymer, using both alkaline activators. However, the CCR will be more appropriate if environmental and economic problems considered.