SAND TYPES

Below are some sand types and their applications in concrete.

Dune/Desert Sand: 0.1 to 1.6 mm (100 - 1600 µm). Not considered viable for construction due to its smooth surface.

Fine Sand: 0.075 mm to 0.425 mm (75 - 4250 µm). Used for plastering, mortar mixes where smooth finishes are required, and fine concrete work.

Concrete Sand (C-Sand): 0.15 mm to 4.75 mm (150 - 4750 µm). This size range is preferred Preferred for construction due to its bonding with concrete and providing strength and durability

Coarse Sand: 2 mm to 4 mm (2000 - 4000 µm) or larger. Used in applications where structural integrity is the primary concern, such as foundations and road construction.

BENEFITS OF DUNE SAND

In many desert regions, there is an abundance of dune sand. Made viable, Dune sand offers a broad spectrum of benefits such as :

Fine Aggregate: Dune sand can serve as a fine aggregate in concrete mixes, potentially replacing or supplementing the river sand shortage.

Cost-Effectiveness: Locally sourced dune sand will reduce transportation costs and reliance on traditional sand sources. 

Environmental Advantages: Utilising dune sand will help conserve resources and reduce the environmental impact of construction projects. 

Workability: Studies suggest an improvement in workability of concrete, when dune sand is used.

Strength: Studies indicate that Dune sand can be used in concrete by up to 40% content, without having negative effects on its strength and durability. 

Backfilling and Embankments: Dune sand can be suitable for backfilling and embankment construction. 

Pavement Interlock Bricks: Dune sand can be used to produce pavement interlock bricks. 

Plastering: Due to its uniformity, Dune sand is ideal for wall plastering and fine concrete work.

INTERFACING DUNE SAND

The absence of microscopic roughness or pores means there's less area for an adhesive to grip and form a strong bond. 

Bonding on smooth microscopic surfaces like Dune Sand can hence be challenging but it is nonetheless achievable by:

• mechanical roughening or chemical treatments

• using adhesives that form strong bonds through chemical interactions

• increasing surface energy

TRADITIONAL CEMENT DEFICIENCIES

The term "cement",does not mean Portland cement. It simply means "binder" or a chemical adhesive. 

This means a cement is not restricted to products like Portland Cement or ground-granulated blast-furnace slag (GGBS or GGBFS). 

At an average particle diameter of 85µm, Ordinary Portland Cement (OPC) is close in size scale to Dune Sand. Rapid hardening cement has particle sizes ranging between 10 µm to 50 µm. So why don't these adhesive materials with surfaces mechanically made rough from grinding, bond firmly with Dune Sand?

Despite being chemical adhesives/cement with particles in a similar size range or even smaller than Dune Sand, the surface area of traditional cements is not high enough to effectuate a strong bond with the smooth surface of Dune Sand micro-particles.

DUNE NANOCEMENT

Smooth surfaces like glass, plastics, metals and Dune Sand, typically have a lower surface energy than most materials. This means, materials like Dune Sand resist bonding.

The critical design factor hence, for bonding concrete effectively with smooth Dune Sand, is a a high surface energy Nano-Cement. Congruently, a high surface area nanomaterial, with an increased affinity to bonding with low energy materials, to increase concrete strength.

In construction, this material parameter is also known as "blaine" (cm²/g) and increases as the material particle size gets finer.

This is the key challenge NANOARC resolves, with its proprietary Dune NanoCement - DUNECEM. 

DUNECEM

With DUNECEM, NANOARC utilises other chemical compositions, to deliver a higher performance nano-cement, with particle dimensions averaging between 1 - 25 nm (0.001 - 0.025 µm). DUNECEM particles are 85000x smaller than traditional cement particles and have a blaine ~ 200x higher than traditional cements as shown below :

GENERAL PURPOSE CEMENT :     3,200 – 3,800 cm²/g

SLAG CEMENT (GGBS)  :                4,000 – 4,500 cm²/g
RAPID HARDENING CEMENT :       4,500 – 6,500 cm²/g

NANOARC DUNECEM :        359,300 - 635,200 cm²/g 

DUNECEM is produced using low-energy, zero CO2 emission sustainable nano-chemistry because such superfine nanoparticles cannot be obtained by grinding.  

DUNECEM offers benefits such as :

• higher reactivity without excessive heat generation,

• strong and effective bonding with concrete components like Dune Sand for higher density and strength, 

• reduced concrete weight

•  low porosity and increased freeze-thaw resistance

• rapid hydration and concrete cure rate

• increased concrete durability

• minimises the need for recurring repairs

DOSAGE

The DUNECEM effective dose* in concrete averages  0.0001 - 0.001 wt%, depending on the desired strength. At a 0.0001 wt % dose, with an average concrete strength gain of 10 - 20% in the first 24 - 72 hours. 

USAGE GUIDELINES : No special equipment is needed. Simply weigh and mix DUNECEM nanopowder thoroughly with your fine aggregate in the dry phase before hydration, then proceed as usual.

*The estimated Dune Sand mixing ratio for concrete is ~ 75% dune sand and 25% river sand. With an alteration in DUNECEM dose, this ratio can be modified further, to favour a higher mix ratio of Dune Sand.

SIMPLIFIED LOGISTICS

The ultra-high blaine of DUNECEM products enables their usage at unconventionally low doses, which lowers logistics costs e.g. 1kg (2.2 lb) of DUNECEM BOND is viable for 370 m3 (440 Yd3) of concrete, shipped from our facility to any worldwide location, at a fixed cost of $105 or 45€ across all of Europe. This compensates for the hefty costs incurred with the shipment of tonnes of conventional cement. 

We help re-design concrete formulations that adopt dune sand.