# Effect of Various Proportions of Rice Husk Powder on Swelling Soil from New Cairo City, Egypt
###### Abstract  
Swelling soil leads to many types of constructional damages, deformations, and failures in the constructions' roads, shoulders, and foundations. Depending on the amount of swell, they can be insignificant, moderate, or massive. This paper presents a method for swelling soil stabilization by adding rice husk powder (RHP) in variable percentages of 0, 5, 10, 15, 20, and 25 by weight of dry soil. The properties of swelling soil stabilization were investigated by various lab tests such as consistency limits (plastic limit, liquid limit, and plasticity index), swelling potential, swelling pressure, free swelling, and free swell index. The swelling soil was also mineralogically examined using X-ray diffraction of clay mineralogy. This stabilization reduced the plasticity from 56% (extremely high plasticity) to 4.5% (low plasticity). Swelling potential (S) and swelling pressure (SP) decreased by 48% to 45.5, 44.7, and 34.6%, from 1003 kN/m\({}^{2}\) to 800, 653, and 489 kN/m\({}^{2}\) for the partial replacement of the soil by 5%, 10%, and 15% RHP, respectively. The results show that the present approach is very efficient for improving the swelling soil properties and that the optimal amount of added RHP of the swelling soil is 15%. It will also be a database aimed at reducing construction risks in the future. engineering properties; swelling soil; rice husk powder; swelling pressure; consistency limits; soil stabilization +
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focus [4], such as fly ash, marble dust, rice husk ash, coir fiber, plastic waste, and nanomaterials [5; 6; 7; 8; 9; 10; 11; 12; 13]. These enhancements include increased dry unit weight, bearing capacity, durability, and volume changes. Any country's development depends on transport installations and construction projects. In order for projects to be successful, foundations need to be strong, requiring better soil properties. The area under investigation is among the most promising areas for cities and tourists and industrial developments in Egypt. New Cairo City is said to be one of the city's new projects. The study area suffers from several problems, the most important of which is the presence of clay layers in the different geological formations, which have a serious impact on urbanization. As experience from different worldwide places shows [14; 15], various clay properties can play a fundamental role in determining geotechnical conditions. The swelling of the soil strongly affected the buildings in the study area, leading to the collapse of many buildings and the presence of numerous cracks in the constructions. The present paper focuses on using RHP to stabilize the swelling soil of the industrial zone of New Cairo City, Egypt. Rice husk ash (RHA) is one type of solid waste that has gained attention in recent years in rice-growing countries such as Egypt, Indonesia, China, and Pakistan. RHA is made from burning rice husk, which is a common agricultural byproduct. RHA production is around 20% of the weight of the rice. When rice husk is burnt, it removes lignin and cellulose from the silica ash. The burning of rice husks causes difficult problems for the government and may impact the environment in general. It has significant negative effects on human health because it absorbs a large number of environmental perturbations and creates what is known as cloud black. This leads to contaminated rainfall, which affects the environment and causes many diseases due to consuming foods contaminated by harmful gases present in the rain. The government should strengthen agricultural waste development through recycling to take full advantage of the increase in pollutants at an abnormal rate. The pollution caused by the rice husk combustion costs the Egyptian economy tens of billions of dollars each year. For the above reasons, the author of this paper used RHP to stabilize swelling soils and convert them from harmful substances to beneficial substances. There is plenty of scientific research to take advantage of rice husk.