Urgent need to find replacement for sand in concrete

 Over 4 billion tonnes of sand is being dug up around the world each year. In a bid to curb environmental and community damage,work is being undertaken to find alternate materials for use by the concrete industry. Graphene has been found to offer an alternative as a replacement for sand in concrete as well as a reinforcing additive. .Geneva University says that Sand resource governance is one of the greatest sustainability challenges of the 21st century. The University helped establish The Global Sand Observatory aimed at developing knowledge and providing decision making support on the sustainability issue of sand extraction and use.

Meanwhile, researchers at Rice University in the US discovered that graphene could be used in place of sand due to sand mining rates outstripping natural replenishment.As sand comprises 30% of concrete, it represents a significant part, according to Satish Nagarajaiah, Professor of Civil and Environmental Engineering and Mechanical Engineering at Rice University.

Other studies have looked at the business awareness of sand substitutes in construction and building materials. The work has generally been inspired by evidence documented by the United Nations and other scientific sources of a global sand crisis and the urgent need to reduce consumption of alluvial sand. The construction industry t is a major consumer of sand.

The United Nations has declared a global sand crisis, called for reduced sand consumption, and proposed solutions to address the crisis, including adopting sustainable substitutes for sand. The construction industry is a major consumer of sand, yet a recent study found a very low level of awareness by stakeholders of the crisis. The purpose of one study was to assess the familiarity of the construction industry with 27 sand substitute materials.156 construction industry professionals took part in the study. They were in 35 US states and 7 Canadian provinces.

The construction industry has made substantial progress in recent years toward addressing the environmental impact of construction materials and developing sustainable substitute materials. A primary objective has been to reduce greenhouse gas emissions, and the focus has been on cement and concrete because of the high volume of their use and their significant contributions to climate change. Globally, concrete production contributes about 5–10% to greenhouse gas emissions (GHGs), with 2.1 billion tons annual anthropogenic GHCs, mostly from cement clinker production [1,2]. Concrete is produced at the rate of about 4 billion tons annually (USG, 2014), and cement, the main binder, comprises 10 to 15% of concrete [3]. Recognizing the magnitude of concrete and cement production globally, researchers have developed numerous alternatives to traditional Portland cement. That type of cement has been the industry standard due to its performance characteristics. However, it needs heating to extremely high temperatures, thereby contributing to greenhouse gas emissions.

Annual global sand consumption is in the range of 32 to 50 billion metric tons [10]. Around 10 billion tons are used in the construction industry, and it is estimated that consumption will nearly double by mid-21st century [11]. Sand is a major ingredient in a wide variety of construction materials, and a number of substitutes have been developed for various applications. Sand contributes 40% of the aggregate used in concrete as well as 25–30% of concrete by volume [3]. Silica, mainly from sand, comprises up to 25% of cement [3]. Mortar consists of 75% sand. Sand is an ingredient in dozens of other building products including glass, ceramics, paints, plastics, rubber, sealants and grouts, adhesives, and resins

concrete and many other sand-related products require natural alluvial sand, which is essentially a non-renewable resource. Other types of sand, such as desert sand, lack the appropriate angularity. Alluvial sand is formed over millennia by entering waterways downstream from mountains, or is created by years of wave action on rocky coastlines; thus, it is not easily replenished. sand mined from inland deposits can interfere with aquifers and natural habitats. Despite the extensive use of sand in construction, it is unclear how well known these substitutes are among industry professionals. This issue has received limited attention in the literature, and much of the work in this area is still limited to the development of new and more sustainable building materials with little attention paid to the end-user perspectives and knowledge of the proposed materials.