Study on the Stabilization/Solidification of Lead-Contaminated Soil Using Alkali-Activated Cementing Materials with Rich-Silicon Materials

2017 ◽  
Vol 1142 ◽  
pp. 291-295
Author(s):  
Min Zhou ◽  
Shu Yan Wu ◽  
Yi Lv ◽  
Wei Xin Wang ◽  
Hao Bo Hou
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Rice Husk Ash ◽  
Cementitious Materials ◽  
Polluted Soil ◽  
Toxicity Characteristic Leaching Procedure ◽  
The Usa ◽  
Silicon Materials ◽  
Alkali Activated ◽  
Leaching Procedure

In this study, the stabilization/solidification of lead in soils using alkali-activated cementing materials with rich-silicon materials was investigated. The artificial Pb-polluted soil with 500mg/kg lead was treated using fly ash-, silica fume-and rice husk ash-based cementitious materials, respectively, at the dosages 25%. The effectiveness of treatment was assessed with unconfined compressive strength (UCS) and the toxicity characteristic leaching procedure (TCLP) after curing for 14 and 28 days. Overall, the UCS results showed that the UCS values are above the USA EPA’s recommended value of 0.35 MPa. The TCLP results indicated that the Pb concentrations extracted from soils amended with 25% cementitious materials after 14 and 28 days are near 0.25mg/L, far below 5mg/L (the TCLP regulatory limit). And the XRD results showed the immobilization of lead were due to the formation of PbSiO3, the sorption of C-S-H.

A Comparison in Metal Leachability Between Phosphoric Acid and Ascorbic Acid Stabilised Ferrochrome Slag

2021 ◽  
Vol 47 (2) ◽  
pp. 207-215
Author(s):  
Thabo Falayi ◽  
Bolanle D. Ikotun
Keyword(s):  
Compressive Strength ◽  
Ascorbic Acid ◽  
Phosphoric Acid ◽  
Metal Ions ◽  
Unconfined Compressive Strength ◽  
Toxicity Characteristic Leaching Procedure ◽  
Ferrochrome Slag ◽  
Leaching Procedure ◽  
Phosphate Compounds

Ferrochrome (FeCr) slag was milled and stabilised with either ascorbic acid or phosphoric acid. The stabilised FeCr was then geopolymerised with 1 M KOH in order to obtain a monolith with at least an unconfined compressive strength of 1 MPa. The leachability of metals of the stabilised geopolymerised monoliths were then compared with the unstabilised geopolymerised monolith. Ascorbic acid stabilisation was only effective in Cr leaching reduction by 99.45% but was not effective on immobilisation of Fe, Zn, Ni and Mn. Ascorbic acid stabilisation was thought to proceed via the reduction of Cr(VI) species to insoluble Cr (III) species. Phosphate stabilisation reduced the leachability of Cr, Ni, Zn, Mn, Fe by 99.5%, 67.1%, 71.1%, 96.8% and 85.4% respectively. Phosphate stabilisation was thought to proceed via the formation of phosphate compounds of the metal ions in question. The phosphate stabilised FeCr slag leachability was within the allowable Toxicity Characteristic Leaching Procedure (TCLP) limits and its use is not detrimental to the environment.

scholarly journals Strength and Durability Performance of Alkali-Activated Rice Husk Ash Geopolymer Mortar

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Yun Yong Kim ◽  
Byung-Jae Lee ◽  
Velu Saraswathy ◽  
Seung-Jun Kwon
Keyword(s):  
Compressive Strength ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Polymerization Reaction ◽  
Strength Development ◽  
Geopolymer Concrete ◽  
Portland Cement Concrete ◽  
Mix Proportion ◽  
Strength And Durability ◽  
Alkali Activated

This paper describes the experimental investigation carried out to develop the geopolymer concrete based on alkali-activated rice husk ash (RHA) by sodium hydroxide with sodium silicate. Effect on method of curing and concentration of NaOH on compressive strength as well as the optimum mix proportion of geopolymer mortar was investigated. It is possible to achieve compressive strengths of 31 N/mm2and 45 N/mm2, respectively for the 10 M alkali-activated geopolymer mortar after 7 and 28 days of casting when cured for 24 hours at 60°C. Results indicated that the increase in curing period and concentration of alkali activator increased the compressive strength. Durability studies were carried out in acid and sulfate media such as H2SO4, HCl, Na2SO4, and MgSO4environments and found that geopolymer concrete showed very less weight loss when compared to steam-cured mortar specimens. In addition, fluorescent optical microscopy and X-ray diffraction (XRD) studies have shown the formation of new peaks and enhanced the polymerization reaction which is responsible for strength development and hence RHA has great potential as a substitute for ordinary Portland cement concrete.

scholarly journals Blended binder system with Incinerated Paper Ash (IPA) for Solidification/Stabilization (S/S)

2018 ◽  
Vol 7 (4.33) ◽  
pp. 491
Author(s):  
Mazni Mat Zin ◽  
Azyan Zafyrah Mohd Zahid ◽  
Noorashiekin Khalid ◽  
Nadia Zalikha Saifullizam ◽  
Wan Syarizawani Wan Chik ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Ordinary Portland Cement ◽  
Binder System ◽  
Sludge Treatment ◽  
Waste Sludge ◽  
New Material ◽  
The Impact ◽  
Leaching Procedure ◽  
Main Material

This research explored the potential to use IPA as a binder for the treatment of industrial waste sludge. Within the study, Incinerated Paper Ash (IPA) was used together Ordinary Portland Cement (OPC), a main material employed in solidification/stabilization (S/S) methodology to treated industrial ceramic sludge. The issues created by OPC in sustain the surroundings and cost force the new material must replace OPC as binder within the treatment methodology. The impact of the various IPA compositions within the system has been examined. The Unconfined Compressive Strength (UCS) and Toxicity Characteristic Leaching Procedure (TCLP) were used to assess the viability of IPA in sludge treatment once 28 days. The great result of compressive strength and decrease in heavy metals shows the potential of IPA in OPC replacement.   

scholarly journals Influence of Rice Husk Ash Density on the Workability and Strength of Structural Concrete

2017 ◽  
Vol 2 (3) ◽  
pp. 36 ◽  
Author(s):  
John Kamau ◽  
Ash Ahmed ◽  
Fraser Hyndman ◽  
Paul Hirst ◽  
Joseph Kangwa
Keyword(s):  
Compressive Strength ◽  
Rice Husk ◽  
Water Demand ◽  
Rice Husk Ash ◽  
Concrete Strength ◽  
High Water ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Hardened Concrete ◽  
Structural Applications

Supplementary cementitious materials (SCMs) have been known to improve the properties of fresh and hardened concrete, and at the same time enhance the sustainability of concrete. Rice husk Ash (RHA), is one such material, but has neither been widely studied nor applied in practice. This work investigated the effect of the density of RHA on the workability and compressive strength of fresh and hardened RHA-replaced concrete respectively. Cement was replaced with RHA in concrete by weight (RHA-W) and by volume (RHA-V) at steps of 0%, 5%, 7.5%, 10%, 15%, 20%, 25% and 30%. The 0% replacement was used as the reference point from which performances were measured. Results showed that unlike the characteristic of other established pozzolans, RHA significantly reduced the workability of wet concrete and the rate of compressive strength gain over curing time due to a high water demand that is caused by the increased volume of replaced concrete, which results from its low density. Workability reduced with increased replacement for both RHA-W and RHA-V. Replacements of above 15% were not possible for the RHA-W due to the high water demand. However, replacements of up to 30% were achieved for the RHA-V. RHA-W specimens achieved lower compressive strengths and were observed to gain strength at a lower rate over the 28 to 91-days period of curing compared to RHA-V specimens. This behavior was attributed to the shortage of water that is necessary for the hydration of cement and subsequent pozzolanic reaction, which is the basis of the contribution that is made to the strength and performance of concrete by SCMs. However, the compressive strengths achieved were above the study’s target concrete strength of class C32/40 at 91 days, which is among those classes that are listed as being durable and suitable for structural applications. A conclusion that RHA should supplement cements by volumetric replacement rather than simple substitution by weight was drawn.

scholarly journals Compressive Strength Characteristics of Cemented Tailings Backfill with Alkali-Activated Slag

2018 ◽  
Vol 8 (9) ◽  
pp. 1537 ◽  
Author(s):  
Gaili Xue ◽  
Erol Yilmaz ◽  
Weidong Song ◽  
Shuai Cao
Keyword(s):  
Compressive Strength ◽  
Mine Tailings ◽  
Low Cost ◽  
Cementitious Materials ◽  
Cementitious Material ◽  
Solid Wastes ◽  
Fine Grained ◽  
Activated Slag ◽  
The Relationship ◽  
Alkali Activated

With the use of glauberite mineral (GM) and sodium hydroxide (SH) alkaline catalysts to stimulate slag powder’s internal cementation activity and incorporate the two fine-grained solid wastes, such as quicklime (Q) and desulfurized ash (DA), a new cementitious material suitable for mine tailings was developed to replace traditional ordinary Portland cement (OPC) for reducing cement-related costs. A series of uniaxial compressive strength (UCS) tests were carried out on cemented tailings backfill (CTB) samples containing different activators. The results showed that (1) the highest UCS values of 14-day and 28-day cured CTB samples were 1.259 MPa and 2.429 MPa, respectively, and the effect of different activator types was in the order of SH > GM > DA > Q and SH > GM > Q > DA; (2) the relationship between UCS and activator dosages followed the function y = ax3 − bx2 + cx − d. Compared with the OPC 32.5 R cemented samples, the minimum strength growth factor was 1.45, and the maximum reached 2.03; (3) the optimal proportion of DA slag formula was 4.5% or 5.0% Q, 19% DA, 2.5% GM, and 0.7% SH. The aforesaid new cementitious materials met the mine’s UCS requirements with a relatively low cost (17.04–17.20 €/ton) and solved the stacking problem of solid wastes on the surface well. Ultimately, this study provides a useful reference for the development of mineral binders.

ALKALI ACTIVATED FLY ASH BASED CONCRETE: EVALUATION OF CURING PROCESS USING NON-LINEAR ULTRASONIC APPROACH

2021 ◽  
pp. 1-26
Author(s):  
Arash Nikvar-Hassani ◽  
Hamad N. Alnuaimi ◽  
Umar Amjad ◽  
Saptarshi Sasmal ◽  
Lianyang Zhang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Unconfined Compressive Strength ◽  
Curing Process ◽  
Ultrasonic Technique ◽  
Ultrasonic Signals ◽  
Non Linear ◽  
Ultrasonic Techniques ◽  
Alkali Activated ◽  
Testing And Evaluation

Abstract This paper investigates the applicability of nondestructive testing and evaluation (NDT&E) method using ultrasonic signals to monitor the curing of alkali activated fly ash based concrete (AAFC). The evaluation was carried out on AAFC specimens with two different water/binder (W/B) ratios of 0.3 and 0.5 and after curing at 60 °C for 7, 14 and 28 days, respectively. The signals are recorded and analyzed using linear and non-linear ultrasonic techniques. The results show that the non-linear ultrasonic technique has a clear advantage over the linear ultrasonic technique when monitoring the curing of AAFC specimens with the lower W/B ratio. However, the specimens with the higher W/B ratio do not undergo proper curing and therefore do not show clear distinctions between the curing times measured from the two ultrasonic techniques. The unconfined compressive strength (UCS) of the AAFC specimens at different W/B ratios and curing times is also measured. The UCS results showed a good correlation with the ultrasonic results.

Leachability of Metal Ions in TCLP Leachate of Solidified Petroleum Sludge

2013 ◽  
Vol 594-595 ◽  
pp. 1094-1098
Author(s):  
Asna Mohd Zain ◽  
Shaaban Md Ghazaly ◽  
Mahmud Hilmi
Keyword(s):  
Metal Ions ◽  
Ordinary Portland Cement ◽  
Rice Husk Ash ◽  
Toxicity Characteristic Leaching Procedure ◽  
Cement Ratio ◽  
Cement Replacement ◽  
Petroleum Sludge ◽  
Water To Cement Ratio ◽  
Leaching Medium ◽  
Leaching Procedure

Toxicity characteristic leaching procedure was executed on solidified petroleum sludge to investigate the metal ions release in leaching medium extractant fluid number 2, U.S.EPA SW-846 TCLP. Nine metal ions from solidified sludge in ordinary Portland cement were evaluated at water to cement ratio of 0.4 to 0.5 and incorporation of 5-15% cement replacement materials. Five cement replacement materials namely, rice husk ash, condense silica fume, activated carbon, fly ash and meta kaolin were selected for solidified sludge in the cement. Solidified sludge with cement replacement materials indicates minimum leachability of metal ions.

Study of Manufacture Process and Properties of Tailings and Slag Based Mine Filling Cementitious Materials

2013 ◽  
Vol 734-737 ◽  
pp. 1077-1081 ◽  
Author(s):  
Jin Xia Zhang ◽  
Shu Xian Liu ◽  
Jun Xie
Keyword(s):  
Compressive Strength ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Raw Materials ◽  
Cementitious Materials ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Manufacture Process ◽  
Alkali Activated

The tailings and slag based mine filling cementitious materials was prepared by sodium silicate and sodium hydroxide alkali-activated tailings and slag. Through the test that the cementing materials in the best ratio of raw materials: when slag and tailings admixture is 1.25, the content of NaOH was 50%, the amount of sodium hydroxide for 50%, water cement ratio of 0.22, under the condition of normal temperature curing 7 days, eventually making a compressive strength of 52.3MPa cementing materials.

Investigation on High Volume Steel Slag - Rice Husk Ash Composite Binder Properties

2014 ◽  
Vol 599 ◽  
pp. 310-314
Author(s):  
Yan Hua Wang ◽  
Jun Cai ◽  
Pin Pin Ding ◽  
Ya Jun Wang
Keyword(s):  
Compressive Strength ◽  
Rice Husk ◽  
Frost Resistance ◽  
Rice Husk Ash ◽  
Steel Slag ◽  
Drying Shrinkage ◽  
High Volume ◽  
Cementitious Materials ◽  
The Novel ◽  
Composite Binder

This paper discussed the possibilities of the processed steel slag and rice husk ash in building mortar replace cement. Experimental results show that after suitable mix designs cube compressive strength of composite binders using can meet the building mortar standard. The novel composite cementitious materials need larger water absorption, but their frost resistance, drying shrinkage, sulfate resistance relate to the pure cement varying degrees upgrade.

Effect of Rice Husk Ash Treatment on the Strength Properties of Oil Contaminated Soils

2013 ◽  
Vol 824 ◽  
pp. 59-65
Author(s):  
Thomas Stephen Ijimdiya
Keyword(s):  
Compressive Strength ◽  
Rice Husk ◽  
Contaminated Soils ◽  
Unconfined Compressive Strength ◽  
Rice Husk Ash ◽  
Evaluation Criteria ◽  
Dry Weight ◽  
Strength Properties ◽  
Treated Soil ◽  
Relative Compaction

Oil contaminated soils (PCS) was treated with up to 6% rice husk ash (RHA) by dry weight of soil. Specimens of treated soil compacted at the energy of the standard Proctor (relative compaction = 100%) were subjected to compaction, unconfined compressive strength (UCS) and California bearing ratio (CBR) tests. The results of laboratory tests show that properties of the treated soil improved with RHA treatment. Peak unconfined compressive strength value of 410kN/m2 was obtained at 2% oil/ Applying the conventional evaluation criteria reveals that soil-oil RHA mixture containing 2% oil/4% RHA, 4% oil/4% RHA and 6% oil/4% RHA yields optimum CBR values of 4.6, 4.4 and 3.5% which does not satisfy the minimum required CBR of 15% for use as a subgrade material in road foundation.

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