Investigating the performance of rice husk ash on the durability of the gravel road surface.
Abstract
Over 70% of the road network in sub-Saharan Africa remains unpaved. These roads will continue
to form a great part of the road networks for the foreseeable future with the adverse impacts from
traffic-generated dust being borne disproportionately by the rural and urban poor. Approximately
75% (300000km) of the total Swedish road network and 20% (20000km) of the national road
network consist of gravel roads. One of the most significant problems associated with gravel roads
is traffic-generated dust emission which contributes to the deterioration of the road surface and
acts as a major source of particulate matter released into the atmosphere, thereby interfering with
road safety, people’s health and, environmental air quality. (Edvardsson, 2010)
National roads host more than 80% of the average daily road traffic on the Ugandan road network
and are a strong driver for social-economic development. To sustain this development and realize
long-term benefits, national roads must be adequately maintained. (BMAU, 2019). Size
distributions of dust particles generated by vehicular traffic on unpaved roadways of sandy or silty
soil have a distinctly bimodal character, with mass mean radii around 4 pm, 45 pm for sandy soil
and 10 pm, 35 pm for silty soil (Pinnick et al., 1985). However, quantitative data on the cost of
impacts of road surface deterioration in developing countries and the benefits of longer-term
solutions aimed at satisfying them are scarce.
The Agricultural sector is facing serious challenges in handling and disposal of wastes which are
produced in large quantities per annum. Several studies have been made on both the physical and
mechanical/engineering properties of these agricultural wastes to investigate their applicability in
road construction. So it is important to make these agricultural wastes eco-friendly by utilizing
them as soil stabilizers. (Engineering, n.d.). Rice husks are primary agricultural products obtained
from paddy. Rice milling produces a by-product known as husk which is surrounded by the paddy
grain. At the time of milling of paddy, about 78% of the weight constitutes rice, broken rice, and
bran and the remaining 22% of the weight of paddy are received as a husk. For every 40 KN of
rice 10kN of husk is produced. RHA has been used for several applications both in the construction
industry and outside, for example, stabilization of the weak subgrade soil during the construction
of paved roads(Engineering, n.d.), also the compacted rice husk ash is a very suitable material as
a final filter for water supply over a wide range of moisture contents because of its small pore size
2
and high permeability(Engineering, n.d.), RHA has also been used for partial replacement with the
cement for sustainable concrete and glass–ceramic works due to its pozzolanic properties such as
high silica content (Dávalos et al., 2021) but no study has looked at the performance of RHA on
the durability of the gravel road surface. Therefore, this study focuses on the performance of RHA
on the durability of the gravel road surface.