Structural stabilization of soil backfill with quicklime

Abstract

The application of quicklime (CaO) to soil backfill for the amelioration of poorly aerated grave soils (sandy loam) was tested in a cemetery in Germany. Two grave simulations (soil pits 9 m × 2 m × 1.6 m, l × w × d) were set up. Variation sans was only excavated and refilled, while in variation qlm, 20 kg quicklime per m3 soil were added to the backfill. Soil matric potential and gas composition were recorded over a period of 24 months in the two refilled pits and in the surrounding undisturbed soil (ref) at the 50 cm and 135 cm depths, respectively. Soil samples were taken in the beginning from ref and in three‐month intervals from the treatments sans and qlm. Soil pH and CaCO3 content, as well as bulk density (ρB), air capacity (AC), air conductivity (kl), and saturated hydraulic conductivity (ks) were measured. Excavation and backfill of the untreated soil (sans) led to an increase in ρB at the 50 and 90 cm depths and decreases in AC, kl, and ks when compared to ref. Quicklime application led to an increase in pH, the formation of CaCO3 in the formerly carbonate‐free soil, consistently reduced ρB, and increased AC, kl and ks. Although the quicklime application did not lead to notably more negative matric potentials, it increased the O2 concentration in the soil air and reduced the CO2 concentration to zero. The results show that the application of quicklime helps the structural amelioration of cemetery soils even at relatively low clay contents.

Experimental and Numerical Analysis Study on Loess‐Lime Structures Used for Lateral Antiseepage in Deep Collapsible Ground Embankment

“…Since the cracks were expanded from top to bottom, the expansion of the cracks would lead to the increase of the water content in the area, and the increase of the water content would promote the collapse, so collapse firstly appeared near the water channel (Figure 7). But in the loess-lime treated area, the loess-lime structure could effectively reduce permeability, because SiO 2 and Al 2 O 3 in loess could react with lime and form new materials, which could improve the impermeability [24].…”

Soil characteristics and tillage can predict the effect of ‘structure lime’ on soil aggregate stability

“…The pozzolanic reactions can result in a more permeable microstructure (Al-Mukhtar et al 2012) but also improved soil strength (Kavak and Baykal 2012). Non-carbonated lime as binders are widely used for improve ment of engineering properties of clay fills, as described by Beetham et al (2015) for example, has also been tested for stabilisation of backfill in earth graves (Zimmermann et al 2016(Zimmermann et al , 2019 and drainage trench backfill (Šaulys and Bastienė 2006). Use of CaO and/or Ca(OH) 2 is much less common in agriculture, despite beneficial effects on physical properties of agricultural soils induced by pure CaO and Ca(OH) 2 , compared with pure CaCO 3 , being documented 40-50 years ago (Berglund 1971;Bohne and Hartge 1984).…”

Analysis of the Mechanical Properties of Cured Sludge by Alkaline Excitation of Phosphogypsum

“…The presence of these pores diminishes the curing effect exerted by calcium oxide on soft soil. Consequently, the curing effect is influenced by precipitation of Ca(OH) 2 during the hydration reaction; while it increases compressive strength to a certain extent, excessive crystal precipitation results in pore formation, which reduces its overall effectiveness [17,18].…”