Effect of Calcium Carbonate on the Mechanical Properties and Microstructure of Red Clay

Abstract

The influence of precipitated calcium carbonate on the strength and microstructure of red clay was studied. Precipitated calcium carbonate was added to red clay at ratios of 0%, 5%, 10%, 15%, and 20%. Shear tests were carried out on the samples to observe the effect of calcium carbonate on the mechanical properties of red clay. The results showed that, with increasing calcium carbonate content, the strength of red clay first decreased and then increased. The maximum strength was obtained for the sample with 20% calcium carbonate. Scanning electron microscopy (SEM) was used to observe the changes in microstructure caused by addition of calcium carbonate. The pores and cracks analysis system (PCAS) was used to quantitatively characterize the microstructure changes detected in SEM images. The addition of calcium carbonate decreased the pore area and increased the total number of pores of red clay. The incorporation of calcium carbonate caused the red clay particles to agglomerate. The higher the calcium carbonate content, the stronger the agglomeration of red clay particles in the soil samples.

Replacement of hydroxyapatite from chicken eggshell waste for ceramic properties improvement

“…The surface morphology tends to be having higher roughness after the addition of hydroxyapatite as seen in the top row of Figure 5A. The presence of Ca 2+ from hydroxyapatite results in the clay particles agglomeration to become larger aggregates 30–32 . This phenomenon can be explained as follows: the positive charge of Ca 2+ diffuses to insert between the negative charges of clay particles causing decrease of the repulsive electrostatic force between the clay particles.…”

“…The presence of Ca 2+ from hydroxyapatite results in the clay particles agglomeration to become larger aggregates. [30][31][32] This phenomenon can be explained as follows: the positive charge of Ca 2+ diffuses to insert between the negative charges of clay particles causing decrease of the repulsive electrostatic force between the clay particles. So, the attractive van der Wal force between clay particles becomes a dominant interaction force resulting in the clay particles agglomeration.…”

Characterizing physical and hydraulic properties of soils in Al-Ahsa, Kingdom of Saudi Arabia

“…This result was reported by many studies in Al-Ahsa or other sites worldwide ( Machette, 1985 ). Obviously, in this case, the increase of CaCO 3 % will increase the pore ratio in soil, which will improve the hydraulic properties to some extent ( Chaudhari et al, 2013 , Chen et al, 2020 , Hafshejani and Jafari, 2017 , Khlosi, 2015 ).…”

“…If the dominant size is within the sand particles range, CaCO 3 behaves as sand with increasing soil bulk density ( Habel, 2013 , Habel et al, 2015 ). On the other hand, if it is sized within silt or clay particles, bulk density ρ will be reduced inversely ( Chaudhari et al, 2013 , Chen et al, 2020 , Jensen et al, 2005 ; Mahdi, 2008 ; Mahdi and Naji, 2015 . Saturation θ s , Field capacity, and wilting point are all part of the SWCC, which means that they behave according to the same factors affecting SWCC position or shape.…”

Influence of Soil Particle Size on the Engineering Properties and Microstructure of a Red Clay

“…Accordingly, it is necessary to consider the impact of the particle size on the roadbed when processing red clay. Furthermore, soil particles with different scales have different modes of action [5,6], resulting in various binding modes between particles. From a microscopic perspective, divergent clay minerals, arrangements, and distribution relationships affect the specific surface area (SSA), micropores, single-grain structure, and cemented structure of soil particles, where van der Waals' force is the main force between particles.…”