Research Project Summary Information
Development of High Performance Concrete Containing Waste Limestone Powder(ST10297-1)
Limestone is a building material used as architectural and commercial stone, concrete aggregates, and in Portland cement production. The sizing of architectural and commercial stone produces fine and coarse limestone powder, an industrial waste that is disposed of in landfills. New York State has numerous limestone quarries producing such waste, resulting in the need for more landfills and creating stress on the environment. Imerys quarry in Gouverneur, NY alone generates approximately 8,000 tons of limestone powder annually.
In collaboration with a leading northern NY ready-mixed concrete supplier, Graymont Materials, the project investigated the properties of high performance concretes containing waste limestone powder, providing a sustainable alternative to land filling the waste. The finer variety of waste limestone powder can be used as a cement substitute in Portland cement because it has about the same mean particle size as cement (20-40 µm), and a high calcium content. Currently fly ash is used as a substitute cementing material but needs to be transported to the concrete plant from the source, incurring high transportation costs. The coarser grade waste limestone powder can be examined for use as a fine aggregate (sand) substitute in concrete.
Reduction in landfill costs to the limestone producer;
Reduction in CO2 emissions and the overall amount of cement used in concrete production;
Energy saved by reducing cement production by a ton would be the equivalent to supplying electricity to run an average American home for 24 days.
The performance of limestone powder was evaluated in cement paste, typical concrete and self-compacting concrete systems. From the assessment of the fresh properties of pastes and concretes with 0%, 10% and 20% of cement replaced by limestone powder, it was found that limestone powder significantly reduces the water demand in the system and allows for better flow and workability. Hardened property tests showed no secondary reaction and thus limestone powder must be considered an inert filler.
However, the limestone powder does aid in the hydration process. Long-term durability studies show a lower chloride resistance when limestone powder replaces cement but when the water to binder ratio is decreased to give similar flow, 10% replacement by limestone powder performs comparably to plain mixtures. Limestone powder is shown to be a beneficial component when producing self consolidating concretes.
The beneficial energy and environmental effects of using limestone powder as a cement replacement material in concretes was quantified. The reduction in cement production by about 100,000 tons could result in energy savings of about 16,000 MWh in New York State, in addition to these 100,000 tons of limestone powder diverted away from landfills.
Attn: Comptroller's Office Po Box 5546
Potsdam, NY 13699
Dr. Narayanan Neithalath
NYSERDA Contact Information
R&D - Mfg Tech & On-Site Pwr