Physical and Mechanical Properties of High Performance Concrete with Alum Sludge as Partial Cement Replacement

Abstract

Alum sludge (AS) is a by-product of water treatment plants that use aluminum salts as a primary coagulant, and is the most widely generated water treatment residual/sludge worldwide. It usually contains colloidal alum hydroxides that are often amorphous species. The present paper examines the influence of AS powder as partial Portland cement type I replacement on the mechanical properties of high-performance concrete (HPC). AS with 90% fineness was passed through a 45 µm sieve (No. 325).The present study used a concrete mix with a fixed water/binder ratio of 0.33 and a constant total binder content of 483 kg/m3.The percentages of the alum sludge by weight of cement were: 0%, 6%, 9%, 12%, and 15%. Slump tests were performed on fresh concrete to measure workability. The mechanical properties, dry densities, compressive strengths, and splitting tensile strengths of the concrete samples were investigated at 3, 7, and 28 days, whereas flexural strength was monitored at the age 28 days. Specimens without AS were compared with those that contained AS. The results revealed that the workability of the concrete consistently increased as the amount of cement replaced with AS increased. It was found that the concrete with 6% AS cement replacement demonstrated improved compressive strength and splitting tensile strength at all ages, compared with the control concrete.

Mechanical properties of concrete with hybrid binder fly ash and thermally activated alum sludge as partial cement replacement

“…It was shown that slump value increased with an increasing percentage of AS added in concrete mixes. Addition of 15% AS produced the highest value of slump, 80 mm, compared to the control concrete mixture, with 60 mm [4]. A similar test was done later to analyse the influence of TAASA on the properties of multi-blended binders of cement with samples having TAASA content varies from 0% up to 25% [5].…”

“…al. [4], analysed the high-performance concrete with raw alum sludge addition on the effect of its physical and mechanical properties. Results show that the drinking water sludge is best to be used at 6% replacement of cement across all ages of the curing period.…”

“…In 2013 and 2014, H. M. Owaid et al [4], [5] analysed the split tensile strength of concrete samples containing 6% drinking water sludge and 15% thermally treated drinking water sludge ash (Table 3). Both studies have shown positive results in increasing durability values.…”

“…Very little research on flexural testing of concrete mixtures consisting of a drinking water treatment residue. Owaid et al [4], in the study of physical and mechanical properties of high-performance concrete with AS addition, found that flexural strength improves on the usage of 6% raw AS (Table 4). They compared the results with a mixture of 0%, 6%, 9%, 12%, and 15% a curing period of 3 to 28 Meanwhile, flexural strength on fly ash concrete was analysed by Nikhil [9], for research on substituting high-volume fly ash concrete (HVFAC) for pavement developments.…”

Influence of Magnesium Sulfate on Self-Compacting Alum Sludge Concrete Incorporating with Pozzolanic Materials

“…(Goncalves et al, 2004) (Tantawy, 2015) determined the calcination temperature of alum sludge at 800 0 C and stated that it is adequate to enhance its pozzolanic properties. Also investigations were conducted and reported on reusing of AS by other researchers (Alqam et al, 2011;Zamora et al, 2008;Owaid et al, 2014;Sales et al, 2011) (Mohammed et al, 2013) (Awab et al, 2012;Miroslav, 2008).…”