Properties of Field Manufactured Cast-Concrete Products Utilizing Recycled Materials

Abstract

This investigation was performed to develop technology for manufacturing cast-concrete products using Class F fly ash, coal-combustion bottom ash, and used foundry sand. A total of 18 mixture proportions with and without the by-products was developed for manufacture of bricks, blocks, and paving stones. Replacement rates, by mass, for sand with either bottom ash or used foundry sand were 25 and 35%. Replacement rates, by mass, for portland cement with fly ash were 25 and 35% for bricks and blocks, and 15 and 25% for paving stones. Analysis of test data revealed that bricks with up to 25% replacement of cement and blocks with up to 25% replacement of cement and sand with recycled materials are suitable for use in both cold and warm climates. Other bricks and blocks were appropriate for building interior walls in cold regions and both interior and exterior walls in warm regions. Paving stones with 15% replacement of cement with fly ash showed higher strength, freezing and thawing resistance, and abrasion resistance than the control specimens.

Use of spent foundry sand and fly ash for the development of green self-consolidating concrete

“…The increase in drying shrinkage due to partial or full replacement with SFS has also been noted by other researchers [6,7]. Khatib and Ellis [6] replaced standard sand with SFS by 25, 50, 75 and 100%, and observed that drying shrinkage increased along with SFS content.…”

“…Loss of strength due to SFS replacement has also been noted by other researchers [6,7] although Siddique et al [1,5] reported improvement in compressive strength with an increase in SFS amounts up to 30%. Kraus et al [10] reported the possibility of a reaction between relic organic materials in SFS (from processing of metals) and chemical admixtures such as HRWRs and viscosity-modifying admixtures, that may cause an increase in air content, and result in strength loss.…”

“…Khatib and Ellis [6] replaced standard sand with SFS by 25, 50, 75 and 100%, and observed that drying shrinkage increased along with SFS content. Naik et al [7] investigated drying shrinkage of concrete blocks, bricks and paving stones by replacing sand with bottom ash and SFS. The concretes (both blocks and bricks) made with SFS or bottom ash showed higher shrinkage than those made with standard sand, a result that is consistent with the current study.…”

“…Naik et al [7] investigated compressive strength and freezing and thawing resistance of concrete blocks, bricks and paving stones by replacing sand with 25 and 35% SFS. Strength losses were observed in the SFS mixtures, but, almost all mixtures satisfied minimum compressive strength requirements in standard specifications for concrete bricks and blocks.…”

Used Foundry Sand in Cement Mortars and Concrete Production~!2010-03-27~!2010-05-03~!2010-07-07~!

“…The compressive strength decrease in cementitious materials is due to the presence of binder in foundry sand, as pointed out in [20,29,30]. The binder, composed by a very fine powder of carbon and clay, causes a loose of contacts and links between the cement paste and the aggregate.…”