Fly Ash Sludge Research Articles

Impact of Integrating Flameless Combustion Technology and Sludge–Fly Ash Recirculation on PCDE Emissions in Hazardous Waste Thermal Treatment Systems

Impact of Integrating Flameless Combustion Technology and Sludge–Fly Ash Recirculation on PCDE Emissions in Hazardous Waste Thermal Treatment Systems

Properties of artificial lightweight aggregates prepared from coal and biomass co-fired fly ashes and sewage sludge fly ash

The use of solid waste such as coal and biomass co-fired fly ashes and sewage sludge fly ash instead of clay and other non-renewable resources to produce lightweight aggregates (LWAs) is conducive to sustainable development. In this study, the effects of co-fired fly ashes, sewage sludge fly ash and quartz sand proportion, sintering temperature and sintering time on the physical properties and microstructure of LWAs are studied by single factor experiment. Experimental results show that the optimal experiment conditions are the raw material ratio of co-fired fly ashes: sewage sludge fly ash: quartz sand = 9: 1: 4, 2 wt% SiC as an expansion agent, and sintering at 1060 °C for 10 min. The LWAs obtained under the above conditions have a bulk density of 0.85 g/cm3, an apparent density of 1.84 g/cm3, a 1-h water absorption of 2.71 %, and a compressive strength of 8.68 MPa, which are in accordance with the GB/T17431.1–2010 standard. Besides, the heavy metal immobilization effect of the LWAs is satisfying, where the heavy metal leaching concentrations meet the standard of GB5085.3–2007. In conclusion, it is feasible to use the raw materials to prepare the LWAs under the above sintering conditions, and the prepared LWAs have high strength and low water absorption.

Preparation and characterization of biomass-ash composites derived from incinerated sewage sludge fly ash after hydrothermal treatment

With the increasing prominence of global environmental issues and the growing demand for sustainable development, biomass composites have attracted widespread attention as candidates for environmentally friendly and renewable construction materials. In this study, environmentally friendly biomass-ash composites (BACs) were fabricated using hydrothermally activated incinerated sewage sludge ash (HT-ISSA) as filler and straw powder with waste sawdust as the biomass matrix for hot pressing. An investigation was conducted into the effect of HT-ISSA on the physical properties of the composite, including the bending strength, compressive strength, and thermal conductivity. The composite prepared with 15 wt% HT-ISSA demonstrated an exceptionally high bending strength (30.60 MPa), compressive strength (44.76 MPa), and low thermal conductivity (0.2380 W/m·K). The enhanced physical properties of the BAC material are attributable to the change caused by hydrothermal treatment of the filler phase. Due to the introduction of hydrated calcium silicate, the cohesion performance of the filler significantly improved, thus leading to strong adhesion and penetration within the matrix. The obtained BAC is applicable for packaging and insulation materials, thus providing an effective solution for the economical and environmentally friendly recycling of incinerated sewage sludge ash and other bulk solid waste. Additionally, it contributes novel insights into alleviating the current shortage of forest resources.

Modification of Concrete Composition Doped by Sewage Sludge Fly Ash and Its Effect on Compressive Strength.

The sustainable development of construction materials is an essential aspect of current worldwide trends. Reusing post-production waste in the building industry has numerous positive effects on the environment. Since concrete is one of the materials that people manufacture and use the most, it will continue to be an integral element of the surrounding reality. In this study, the relationship between the individual components and parameters of concrete and its compressive strength properties was assessed. In the experimental works, concrete mixes with different contents of sand, gravel, Portland cement CEM II/B-S 42.5 N, water, superplasticizer, air-entraining admixture, and fly ash from the thermal conversion of municipal sewage sludge (SSFA) were designed. According to legal requirements in the European Union, SSFA waste from the sewage sludge incineration process in a fluidized bed furnace should not be stored in landfills but processed in various ways. Unfortunately, its generated amounts are too large, so new management technologies should be sought. During the experimental work, the compressive strength of concrete samples of various classes, namely, C8/10, C12/15, C16/20, C20/25, C25/30, C30/37, and C35/45, were measured. The higher-class concrete samples that were used, the greater the compressive strength obtained, ranging from 13.7 to 55.2 MPa. A correlation analysis was carried out between the mechanical strength of waste-modified concretes and the composition of concrete mixes (the amount of sand and gravel, cement, and FA), as well as the water-to-cement ratio and the sand point. No negative effect of the addition of SSFA on the strength of concrete samples was demonstrated, which translates into economic and environmental benefits.

WITHDRAWN: Effects of pH on Ochrobactrum immobilises heavy metals during fly ash–sludge​ co-pyrolysis

In order to determine the optimal pH at which Ochrobactrum immobilises heavy metals during fly ash-sludge co-pyrolysis, we investigated the effects of pH on Ochrobactrum to adsorb or desorb heavy metals. The metallic forms of copper (Cu), zinc (Zn), and manganese (Mn) under different pH conditions during co-pyrolysis were analysed using the sequential extraction procedure (BCR). The stabilising mechanisms of Cu, Zn, and Mn caused by Ochrobactrum under different pH conditions during co-pyrolysis were characterised with Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Results indicated the following: (1) The heavy metals immobilised by Ochrobactrum were significantly affected by pH during fly ash-sludge co-pyrolysis. (2) The stable forms of Cu, Zn, and Mn increased most noticeably under neutral and weak alkaline conditions. (3) The neutral and weak alkaline conditions favoured the formation of crystallised materials as well as the preservation of chemical bonds. The results suggested that the effects of Ochrobactrum on the immobilisation of Cu, Zn, and Mn under neutral and weak alkaline conditions were optimal. The results of the study can provide a reference and basis for the harmless disposal of municipal sludge and fly ash and the efficient utilisation of Ochrobactrum . • pH had an effect on Ochrobactrum during fly ash-sludge co-pyrolysis. • pH 7 and pH 9 could improve the stabilisation of heavy metals by Ochrobactrum . • pH 7 and pH 9 could promote the preservation of the chemical bonds by Ochrobactrum . • pH 7 and pH 9 could promote the formation of crystallised materials by Ochrobactrum .

The development of an eco-friendly cold mix asphalt using wastewater sludge ash

The aim of this research was to develop a sustainable and ecologically sound, non-traditional cold mix asphalt (CMA) that can be used in the construction industry. This new type of CMA incorporates wastewater sludge fly ash (UFA) and bottom ash (UBA) as a replacement filler for ordinary Portland cement and limestone. Silica fume (SF) was also used as an additional filler. The mechanical and durability characteristics of the new CMAs were examined in terms of indirect tensile stiffness modulus (ITSM), and rutting, fatigue, water and fuel resistance. The results showed that CMA with 2.1% OPC +3.9% UFA at 3 days of age, had ITSM values 11 times that of traditional CMA, while CMA with 2.1% OPC+ 3.3% UFA +0.6% UBA, had ITSM values 5 times that of traditional CMA at 28 days of age. SF activated hydration for both mixes, significantly increasing ITSM. These results indicate that CMA has a comparable mechanical performance to standard Hot Mix Asphalt (HMA) mixtures for use as surface pavement layers. This study offers a novel CMA with improved mechanical performance. It is economically effective and ecologically beneficial, compared to HMA, due to its ability to accommodate wastewater sludge ashes that are often disposed of in landfill sites.

Co-pyrolysis of municipal solid waste (MSW) and biomass with Co/sludge fly ash catalyst

Catalytic co-pyrolysis of municipal solid waste (MSW) and biomass pine sawdust (PSD) under sludge fly ash (SFA) could be a breakthrough towards the energy challenges and waste management. This paper aims to develop a unique cobalt-alkali-SFA (Co-A-SFA) catalyst, in order to investigate its influence under optimal operating conditions in a fixed bed reactor for syngas production. The catalytic activity was assessed under different Co loading and support ratios. The results indicated that in the presence of Co-A-SFA catalyst, gas production increased due to alkali pretreated fly ash catalyst. Moreover, increasing the Co loading from 5 wt% to 10 wt%, the syngas production increased irrespective of the individual feedstock ratios. Under catalytic conditions of 5 and 10 wt% the H2 yield to 25.4% and 28.3% for 50/50 MSW/PSD compared to 11.5 wt% under no catalyst. Catalytic co-pyrolysis of MSW and PSD also minimized the concentration of complex liquid compounds and heavy hydrocarbons. Therefore, this study establishes a new approach towards energy production and sustainable waste management through useful resource utilization of MSW, PSD and SFA. The outcomes acquired in this investigation showed that blended feedstock in co-pyrolysis of MSW and pine sawdust could enhance production of valuable syngas under SFA-based catalyst.

Preparation of polyaniline/sludge fly ash with improved electromagnetic microwave absorption performance

Transforming solid waste into a functional material is a vital technology that protects the environment and gets high value-added products. The polyaniline (PANI) and sludge fly ash (SFA) composites were fabricated by a facile interfacial polymerization in this study. The structure, composition and morphology of PANI/SFA were investigated in detail. The results showed that with increasing the content of SFA, the electromagnetic microwave absorption properties of PANI/SFA composites first increase then decrease, and it almost stays the same in the end. When the content of SFA is 0.4 g, the composite has an optimal reflection loss of −54.11 dB (thickness of 2.82 mm) at 10.00 GHz and a broad effective absorption bandwidth of 4.08 GHz (RL < −10 dB). The excellent electromagnetic microwave absorption properties are attributed to the synergistic effect of dielectric loss and magnetic loss. These electromagnetic microwave absorbers have potential application prospects.

Highly Effective Adsorption Process of Ni(II) Ions with the Use of Sewage Sludge Fly Ash Generated by Circulating Fluidized Bed Combustion (CFBC) Technology.

Recently, more and more attention has been paid to the removal of nickel ions due to their negative effects on the environment and human health. In this research, fly ash obtained as a result of incineration of municipal sewage sludge with the use of circulating fluidized bed combustion (CFBC) technology was used to analyze the possibility of removing Ni(II) ions in adsorption processes. The properties of the material were determined using analytical methods, such as SEM-EDS, XRD, BET, BJH, thermogravimetry, zeta potential, SEM, and FT-IR. Several factors were analyzed, such as adsorbent dose, initial pH, initial concentration, and contact time. As a result of the conducted research, the maximum sorption efficiency was obtained at the level of 99.9%. The kinetics analysis and isotherms showed that the pseudo-second order equation model and the Freundlich isotherm model best suited this process. In conclusion, sewage sludge fly ash may be a suitable material for the effective removal of nickel from wastewater and the improvement of water quality. This research is in line with current trends in the concepts of circular economy and sustainable development.

Cementitious eco-composites and their physicochemical/mechanical properties in Portland cement-based mortars with a lightweight aggregate manufactured by upcycling waste by-products

Abstract This article presents testings’ results of cement composites with Composite Lightweight Aggregates (CLAs) as a partial substitute of natural aggregates. A new sustainable eco-composite manufacturing took place in laboratory conditions by using 100% waste by-products: PET flakes and sewage sludge fly ash (ssFA) streams or siliceous fly ash (FA). The manufactured (EN 196-1) modified cement mortars were tested in a various series of CLAs by applying volume replacements of 10% and 25% regarding the standard aggregate. The new insights on physical-chemical properties of the original materials and effective water and mechanical performance of both the fresh and hardened specimens contrasted the qualitative and quantitative assessments in the function of the two different aggregates production methods lines. Frattini test is also used to assess the impact of the aggregate composite on the cement composite and their mutual interactions. The obtained results show that the use of CLA as a substitute of standard aggregate allows reducing the water content in the mix while maintaining good workability and increasing compressive and flexural strengths up to 25% of reference mortar.

Lightweight PET based composite aggregates in Portland cement materials - Microstructure and physicochemical performance

This article presents testing results of cement mortars, in which Composite Lightweight Aggregates (CLA) obtained in laboratory conditions substitutes a part of natural aggregates. The new aggregates are sustainable products obtained by using 100% waste by-products: PET flakes and sewage sludge fly ash (ssFA) streams or siliceous fly ash (FA). The level of natural aggregate replacement by CLAs in mortars was 10% and 25% by vol. The purpose of the research was to assess the physicochemical properties of fresh and hardened mortars in the context of the quality assessment of two methods of producing CLAs and the type of fly ash used as their integral components. Surface modification of PET using both types of fly ash improves the useable properties of the obtained mortars compared to mortar using unmodified PET. In case of CLA aggregate based on PET and FA, no symptoms of depolymerization of polyethylene terephthalate were observed in the presence of alkali from cement paste. In case of mechanical properties modelled with CLA composite, an increase in compressive or flexural strength has been observed due to the possibility of lowering the w/c ratio in CLAs mixtures without loss of workability. Replacing only a small part of the natural aggregate with CLA aggregate allows for a double ecological aspect: saving of natural resources and full management of problematic plastic and mineral waste. Cement composites with composite lightweight aggregates may be ecosolution for a number of applications for building engineering like ordinary concrete, small pre-cast or modulus concrete.

Thermogravimetric analysis and pyrolysis product characterization of municipal solid waste using sludge fly ash as additive

MSW pyrolysis was performed in a fixed-bed reactor at 700 °C and sludge fly ash (SFA) was used as an additive. Only organic fractions of MSW were considered. The yield of the products was compared under three conditions: without SFA, with 5% SFA and with 10% SFA. TG-FTIR was also performed on the single, mixed and SFA fractions of MSW to determine the kinetic parameters of the feedstock. The plastic and rubber fractions were the most useful fractions of MSW. Kinetic analysis showed that addition of SFA resulted in the reduction of the apparent activation energy (E). With SFA pyrolysis, the liquid yield decreased from 20.8% to 6.4% and the gas yield increased from 65.5% to 76.4% with 5% SFA and then, decreased to 73.2% with 10% SFA. The major active species in SFA (CaO, SiO2 and Fe2O3) greatly promoted tar cracking effect, resulting in greater gas and lower liquid yield. Addition of 5% SFA, proved to be the most feasible condition, because of higher H2 yield, lowest char yield and better quality liquid product. Thus, concentration of SFA additive proved to be an important factor in products formation of MSW pyrolysis. The possible ecological risk valuation of heavy metals in chars showed the RI values, with 5% and 10% SFA, as 49.02 and 65.10, respectively. This work demonstrated that addition of sludge fly ash played a vital role in the pyrolysis of MSW.

Investigation of Sludge Gasification under Flue Gas

This paper presents the study of sludge gasification under different model flue gases for supporting the development of dual bed gasifier. There are three model gases including 16%O2/N2, 16%O2/20%CO2/N2 and 16%O2/20%CO2/40%H2O/N2, as well as fly ash containing groups. The combustible gas yields were in the range of 247.8–417.3 L/kg sludge, the heating values of the producer gas were in a range of 2,881.8–6,617.3 kJ/m3, and the gasification efficiency were in a range of 46.43–74.56%. CO2 and H2O had beneficial effect on combustible gas yield, gasification efficiency, and LHV of the producer gas. CO content increased while the content of H2 decreased after CO2 introduction. When H2O was added into model gas with the ratio of 40%, H2 concentration in producer gas was remarkably increased as well as improved the overall yield, gasification efficiency, and thus resulting in a gas with a higher LHV. On the other hand, sludge fly ash added in the gasification atmosphere had a negatively effect on combustible gas yield, causing lower heating value of the producer gas. Based on the monitoring of gasification process, the LHV of produce gas can increase 2 to 3 times, possibly up to 17 MJ/m3 by controlling the proper reaction time. The findings can lead to the optimal design of gasifier and reaction to produce high value clean energy.

Growth performance, metal accumulation and biochemical responses of Palak (Beta vulgaris L. var. Allgreen H-1) grown on soil amended with sewage sludge-fly ash mixtures.

Agricultural utilization of sewage sludge (SS) and fly ash (FA) has become both, a common practice and an alternative disposal method for these wastes all around the world. The present study was conducted to assess the effect and viability of co-application of SS and FA (SLASH) in four mixing ratios denoted as A [4 (SS): 1(FA)], B [4 (SS): 2 (FA)], C [4 (SS): 3 (FA)] and D [4 (SS): 4(FA)] at three application rates viz. 20, 40 and 60% (w/w) with agricultural soil on biochemical, physiological and growth response of Palak (Beta vulgaris L. var. Allgreen H-1), a commonly used green leafy vegetable. SLASH amendment modified the physico-chemical properties of soil and increased the concentration of heavy metals (Cd, Cr, Cu, Fe, Ni, Pb, Zn) in soil and plant parts however, within the Indian permissible limit except for Cr, Cd and Zn in shoot. Experimental results revealed decrease in morphological and growth parameters such as root and shoot length, leaf area, root, shoot biomass etc. Lipid peroxidation, ascorbic acid, proline and protein content increased however, total chlorophyll and carotenoid content decreased indicating towards heavy metal stress induced biochemical and physiological response in Palak plants. Significant increase in yield was seen in some of the treatments viz. three mixing ratios B, C and D, with maximum increment shown by mixture D at 20 and 40% amendment rate. The results of this study suggest that though SLASH amendment for growing Palak improved the physico-chemical properties of soil amended and also the yield of the plants in some treatments, it may not be a good option due to risk of contamination of heavy metals such as Cr, Cd and Zn showing higher accumulation.

Upgrading and Evaluation of Waste Paper Sludge Ash in Eco-Lightweight Cement Composites

AbstractThe upgrading and evaluation of waste paper sludge fly ash (PsFA) as a cement substitute in wood-wool composite boards (WWCB) is investigated in the present study. This type of board is wid...

Comparison of Different Leaching Methods for Heavy Metals in Sludge Fly Ash and Comprehensive Toxicity Evaluation

Fly ash from sludge incineration was separated into five different sizes (<1 μm, 1-2.5 μm, 2.5-10 μm, 10-50 μm, and > 50 μm) by high-precision air classification equipment. The leaching of heavy metals was contrastively studied using the HJT 299-2007-sulfuric acid/nitric acid method, HJ 557-2009-Horizontal Oscillation Method, toxicity characteristic leaching procedure (TCLP), and European standard protocol (EN 12457-3) for the different size fractions of the fly ash. Based on the leaching results, an evaluation method for the comprehensive toxicity of heavy metal leaching was established. The results show that the content of heavy metals and the amount of leaching from the fly ash decrease with the increase in fly ash particle size. The leaching of the heavy metals Zn and Cu in the < 1 μm particle size range of TCLP leaching method was the highest, at 107.34 mg·kg-1 and 318 mg·kg-1, respectively. The TCLP and sulfuric acid/nitric acid methods of heavy metal leaching were more effective than the EU (EN 12457-3) and horizontal oscillation methods. According to the value of OPTI, the OPTI value of < 10 μm fly ash was much larger than that of fly ash that was > 10 μm. This indicated that the fly ash of particle size < 10 μm was more toxic and more harmful.

Unit weight, strength and microstructure of a water treatment sludge–fly ash lightweight cellular geopolymer

A water treatment sludge–fly ash lightweight cellular geopolymer (WTS–FA LCG) is investigated in this research with the intention to develop an alternative green construction and building material, without using Portland cement as a cementing agent. Two waste by-products: WTS from the Bang Khen water treatment plants of the Metropolitan Water Work Authority of Thailand (MWA) and FA from the Mae Moh power plants of the Electricity Generating Authority of Thailand (EGAT) were used as an aggregate and a precursor, respectively. The liquid alkaline activator (L) used was a mixture of sodium silicate solution (Na2SiO3) and sodium hydroxide solution (NaOH). The unit weight and strength of WTS–FA LCG heated at 65°C for various influential factors are investigated and presented in this paper. The various influential factors studied include mixing ingredient (air content (Ac), liquid alkaline activator content (L) and Na2SiO3/NaOH), heat duration and curing time. Scanning electron microscopy (SEM) analysis was undertaken to investigate the role of influential factors on unit weight and strength. The test results indicate that the L content at liquid limit state (LL) is optimal for manufacturing WTS–FA LCG for all Na2SiO3/NaOH ratios, heat durations and air contents tested for which the highest strength is attained. Although the unit weight of WTS–FA LCG significantly reduces when L>LL, it is not economical to manufacture WTS–FA LCG at L>LL due to the drastic strength reduction. The addition of Ac at L=LL is found to be an appropriate means to reduce the unit weight and minimize the strength reduction. The maximum strengths at L=LL for various air contents are found at Na2SiO3/NaOH of 80:20 and heat duration of 72h. The longer heat durations of 96 and 120h cause the loss of moisture, thereby resulting in micro-cracks and strength reduction. The WTS was found to be viable alternative aggregate to develop WTS–FA LCG, thereby resulting in this waste material traditionally destined for landfills to be used sustainably as a valuable resource.

Durability against Wetting–Drying Cycles of Water Treatment Sludge–Fly Ash Geopolymer and Water Treatment Sludge–Cement and Silty Clay–Cement Systems

AbstractThe viability of using two waste materials, water treatment sludge (WTS) and fly ash (FA), for developing sustainable masonry units has been previously investigated in terms of strength but the important aspect of durability against wetting–drying (w–d) cycles has yet to be studied. A study on durability against w–d cycles, an important parameter for service life design of the sustainable masonry units, is investigated in this paper. The liquid alkaline activator (L) was a mixture of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH), and a high calcium fly ash (FA) was used as a precursor. The results of cyclic w–d test indicate that the WTS–FA geopolymer manufactured with an optimum ingredient (L:FA=1.6, Na2SiO3:NaOH=90∶10) and at an optimum heat condition of 85°C for 72 h can be used as durable bearing masonry units; i.e., the compressive strength is greater than 12 MPa after 12 w–d cycles. For this optimum ingredient, the w–d cycle strength, qu(w−d) at heat temperatures between 65 and 95°C ...

Compressive strength development in fly ash geopolymer masonry units manufactured from water treatment sludge

A novel water treatment sludge–fly ash geopolymer is investigated in this research with the intention to develop an alternative green construction and building materials, without the usage of Portland cement as a cementing agent. Two waste by-products namely water treatment sludge from the Bang Khen water treatment plants of the Metropolitan Waterworks Authority of Thailand (MWA) and fly ash (FA) from the Mae Moh power plants of the Electricity Generating Authority of Thailand (EGAT) were used in this research. The liquid alkaline activator, L used was a mixture of sodium silicate solution (Na2SiO3) and sodium hydroxide solution (NaOH). This article investigates the effect of the various influential factors on compressive strength of sludge–fly ash geopolymer. The various influential factors studied are mixing ingredient (L content and Na2SiO3/NaOH ratio), heat condition (temperature and duration) and curing time. Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) analyses were undertaken to understand the role of influential factors on strength development. Test results show that the optimum ingredient providing maximum unit weight and strength is Na2SiO3/NaOH ratio of 80:20 and L/FA ratio of 1.3, irrespective of heat condition and curing time. The optimum heat temperature and duration for the optimum ingredient are 75°C and 72h, respectively. The higher heat temperature of 85°C causes the loss of moisture, which results in micro-cracks and strength reduction. The water treatment sludge traditionally destined for landfill can be used in a sustainable manner to develop geopolymer masonry units, with their compressive strengths comfortably meeting the Thailand Industrial Standards.

Compressive strengths of water treatment sludge-fly ash geopolymer at various compression energies

Sludge-fly ash geopolymer is a green material, which does not require cement as a cementitious binder. Sludge and fly ash (FA) are both by-products from Bang Khen water treatment plants and Mae Moh power plants, respectively. A liquid alkaline activator, L is a mixture of sodium silicate solution (Na2SiO3) and sodium hydroxide solution (NaOH). This article investigates the influence of compression energy (E) on the Unconfined Compressive Strength (UCS) of a novel sludge-fly ash geopolymer. The optimal liquid alkaline activator (L) content, sodium silicate solution to sodium hydroxide solution ratio (Na2SiO3/NaOH), heat temperature (T) and heat duration (D), providing the maximum UCS for each E is also investigated. Test results indicate that the optimal L/FA ratio decreases as E increases. The optimal L/FA ratios for E = 592.5, 1346.6 and 2693.3 kJ/m3 are 1.5, 1.4 and 1.3, respectively. The Na2SiO3/NaOH ratio of 80:20 is considered as optimal for all E tested. The UCS of sludge-FA geopolymer at all E values tested increases with an increase of heat duration until a heat duration of 72 hours, after which the UCS becomes almost constant. The heat temperature accelerates the geopolymerization reaction and therefore enhances the strength. However, overheating results in micro-cracks in the samples due to the loss of moisture. As such, the optimal temperature is controlled by liquid content; the higher L/FA results in the lower optimal heat temperature. Since the optimal L/FA ratio decreases as E increases, the optimal T subsequently decreases with an increase in E; i.e., its values are 75, 85 and 95 oC for E = 2693.3, 1346.6 and 592.5 kJ/m3, respectively. The maximum UCS values of sludge-FA geopolymer at optimal ingredient and heat condition are 20, 18 and 16 MPa for E = 2693.3, 1346.6 and 592.5 kJ/m3, respectively, which meet the strength requirement of bearing masonry units as specified by the Thailand Industrial Standard (TIS).