Soil stabilisation with lime-activated-GGBS—A mitigation to flooding effects on road structural layers/embankments constructed on floodplains

The durability of compressed earth-based masonry blocks

“…Early micro-cracking that may go unchecked could lead to very expensive remedial measures if left unattended. Damage due to water ingress is perhaps the most common in masonry, as materials in general lose strength upon wetting (Adedeji, 2002;Baojian, Chisun, & Caijun, 2013;Forth, Brooks, & Tapsir, 2000;Kelman & Spence, 2004;Walker, 2004;Obuzor, Kinuthia, & Robinson, 2011a,b;Obuzor, Kinuthia, & Robinson, 2012). Water ingress can be due to flooding or underground water flows or by way of capillary rise.…”

“…The water spray method (see typical set-up in Figure 18.12) is also fairly common for assessing water damage and durability (Guetalla et al, 2006;Obonyo, Exelbirt, & Baskaran, 2010;Cid-Falceto et al, 2012, among others). Typical erosion rates for various masonry materials upon water spraying of unfired masonry are provided in Table 18.1, after the research work by Obonyo et al, 2010), while Table 18.2 shows typical strength reduction values for compressed earth stabilized using a blended binder consisting of lime and GGBS, from work by Obuzor, Kinuthia, & Robinson (2012). It is reiterated that these typical values by Obonyo et al (2010) or by Obuzor et al (2012) can change significantly upon changes in material composition and small changes in test conditions, among other factors, and should be interpreted, used or extrapolated with great caution and care, as the following analysis will demonstrate.…”

“…Typical erosion rates for various masonry materials upon water spraying of unfired masonry are provided in Table 18.1, after the research work by Obonyo et al, 2010), while Table 18.2 shows typical strength reduction values for compressed earth stabilized using a blended binder consisting of lime and GGBS, from work by Obuzor, Kinuthia, & Robinson (2012). It is reiterated that these typical values by Obonyo et al (2010) or by Obuzor et al (2012) can change significantly upon changes in material composition and small changes in test conditions, among other factors, and should be interpreted, used or extrapolated with great caution and care, as the following analysis will demonstrate. The work by Guettala et al (2006) used a target material with the following soil characteristics: 64% sand, 18% silt, and 18% clay, with a chemical composition analysis showing 5.81% sulfate as SO 3 .…”

The Effect of Heat on the Properties of Expansive Clay Soil

“…Further, suitable borrow materials continue to deplete, with their locations getting further and further from the location where they would be required. Yang and Zheng (2006) as cited in Obuzor et al (2012) give the classical option for road construction in flood plains with troublesome materials which has always been to excavate and import good material for replacement. According to Prusinski and Bhattacharja (1999) and Yang and Zheng (2006) as cited in Obuzor et al (2012) excavation and importing material for replacement has huge cost implications due to increase in carbon footage resulting from burning fossil fuel or cost due to damage to the environment resulting in increase in greenhouse gases, responsible for global warming.…”

“…There is thus need to continually research into methods of improving expansive clays in place. Most research methods currently concentrate on attempting to stabilize this soil; according Obuzor et al (2012) lime stabilization has been used for many years to improve soil properties. This research looked into the effect of heating the expansive clays to 600 0 Cand to determine if it would be suitable for use as fill material as an alternative to either lime stabilization or replacement with suitable material.…”