Use of wood-ash and crumb rubber in building materials to improve eco-friendly construction

Abstract

Mortar is one of the most popular products used in modern construction. It consists of sand, cement, and water. Due to its composition, the production of mortar and its use in construction greatly increases pollution. Scientists are working hard on finding alternatives to mortar, reducing the risk of pollution, and making eco-friendlier construction materials. One of the methods developed is partially replacing the different composition of mortar with wood-ash and crumb rubber. Wood ash is made of fly ash and bottom ash. It is the result of the incineration of wood, and is usually disposed of in landfills, which is a dangerous practice. Landfill space is also decreasing greatly as years go by. In addition, tires rubbers are unrecycled polluters. The amount of unrecycled rubber is getting higher every year due to the car manufacturing growth that may result in harmful impacts to the environment. The purpose of this research project is to study the effect of partially replacing cement with wood ash, replacing sand with wood ash, and replacing sand with crumb rubber in mortar mixes, and then combining them all to select the most economical and effective mixture. A reference mix with 0% partial replacements, as well as a mixes with different percentages of wood ash as partial cement replacement were prepared (from 1% to 20%), mixtures of wood ash as partial sand replacement were prepared (from 1% to 20%), and mixtures of crumb rubber as partial sand replacement were also mixed (from 1% to 20%). A final mixture (a combination of all three components: wood ash as partial cement replacement, wood ash as partial sand replacement, and crumb rubber as partial sand replacement) with the best results was prepared and tested. The compressive and flexural strength of all the different mixtures were measured and examined on the seventh, 14th, and 28th days, while the slump test was performed immediately following the mixing process. The final outcome was as followed: 4% of cement being replaced with wood ash, 20% of sand replaced with wood ash, and 2% of sand replaced with crumb rubber yielded the most acceptable results in terms of flexural strength and compressive strength.