This chapter describes the methodology used in EPA’s Waste Reduction Model (WARM) to estimate streamlined life-cycle greenhouse gas (GHG) emission factors for concrete beginning at the point of waste generation. The WARM GHG emission factors are used to compare the net emissions associated with concrete in the following two waste management alternatives: recycling and landfilling. Exhibit 1 shows the general outline of materials management pathways for concrete in WARM. For background information on the general purpose and function of WARM emission factors, see the Introduction & Overview chapter. For more information on Recycling and Landfilling, see the chapters devoted to these processes. WARM also allows users to calculate results in terms of energy, rather than GHGs. The energy results are calculated using the same methodology described here but with slight adjustments, as explained in the Energy Impacts chapter.

나의 Concrete 연구실

A review of waste products utilized as supplements to Portland cement in concrete

Sulfuric acid resistance of blended ash geopolymer concrete

Supplementary cementitious materials origin from agricultural wastes - A review

A huge number of artificial waste material can be supplementary cementitious material (SCM) for concrete production – a review part II

Flexural performance of green engineered cementitious composites containing high volume of palm oil fuel ash.

The strength activity index of mortar and microstructural characteristics of pastes containing treated palm oil fuel ash (POFA) have been investigated. POFA obtained from a palm oil mill was treated via sieving, grinding and heating at temperature of 450°C for 90 minutes in order to improve the pozzolanic reactivity of the POFA. The pozzolanic reactivity of the treated POFA was evaluated by conducting strength development tests according to ASTM C311. The hydration products of hardened pastes were analyzed by means of thermogravimetric analysis (TGA), x- ray diffraction (XRD), and scanning electron microscopy (SEM) in order to quantify the influence of the treated POFA which was used at different POFA/cement ratio ranging from 0 to 0.8. After 28 days, the strength activity index of the treated POFA with ordinary Portland cement exhibited very good performance and was higher than 100%. At 90 days, the strength activity index increased to 101.72 %. Using TGA, XRD, and SEM, a significant reduction in Ca(OH)2 content was observed with increasing amount of treated POFA. The development of C-S-H gel was higher when POFA/cement ratio was raised up to 0.3.

http://www.ijens.org/Vol_11_I_05/115905-7676-IJCEE-IJENS.pdf

Strength Activity Index and Microstructural Characteristics of Treated Palm Oil Fuel Ash

Palm oil fuel ash obtained from palm oil mill was treated via screening, grinding and heating to improve its pozzolanic reactivity. The characteristics of the palm oil fuel ash before and after treatment were monitored to assess the changes in the properties of the palm oil fuel ash. The resulting ultrafine palm oil fuel ash was then utilized to produce high strength concrete by replacing the ordinary Portland cement at 0, 20, 40 and 60% on mass-for-mass basis. The results show that the treatment process undertaken reduces the particle size, diminishes the unburned carbon content, while at the same time increases the glassy phases. The utilization of the ultrafine palm oil fuel ash in high strength concrete was observed to improve workability especially at higher ultrafine palm oil fuel ash content. In addition, the long-term compressive strength of the high strength concrete was significantly increased with the ultrafine palm oil fuel ash inclusion. Further, the long-term rapid chloride permeability was significant reduced especially at higher ultrafine palm oil fuel ash content of 60%, which could be translated into superior durability performance.

Characteristics of Treated Palm Oil Fuel Ash and its Effects on Properties of High Strength Concrete

The influence of palm oil fuel ash (POFA) inclusion on the compressive properties and chloride resistance of engineered cementitious composites (ECC) were experimentally investigated. In the material development, pozzolanic reactivity of POFA, direct tensile test and matrix fracture test were performed for evaluating the performance of ECC with POFA. Different ECC mixes with varying POFA content and water–binder ratios were used. The results show that the use of POFA should be helpful for achieving strain-hardening behavior by enhancing the fracture toughness and interfacial bond between matrix and PVA fiber. Moreover, at 28 and 90 days, increasing the POFA/cement ratio up to 0.2 led to an increase in the compressive strength of the ECC. The ECC mix with 1.2 POFA–cement ratio achieved a compressive strength of 30 MPa at 28 days, which is within the normal range of concrete strength for many applications. In addition, the test results show that mechanically pre-loaded POFA–ECC specimens exposed to chloride solution remain durable. The results also indicated strong evidence of self-healing of micro-cracked POFA–ECC specimens, which can still carry considerable flexural load. The rapid chloride permeability test reveal that the total charge passed was gradually reduced with the inclusion of higher amount of POFA. The results presented in this study provide a preliminary database for the durability of cracked and uncracked POFA–ECCs under chloride environment or/and combined mechanical loading.

Influence of treated palm oil fuel ash on compressive properties and chloride resistance of engineered cementitious composites

The present paper is a part of an extensive study on green palm oil fuel ash engineered cementitious composites conducted at Universiti Sains Malaysia. It specifically investigates the effects of waterbinder ratio (w/b) and palm oil fuel ash (POFA) on the drying shrinkage of engineered cementitious composites (ECCs). W/b values of 0.33, 0.36, and 0.38 were selected. ECC mixes were proportioned to have various ratios of POFA ranging from 0 to 1.2 from the mass of cement. The drying shrinkage measurements were taken at 4, 11, 18, 25, 57, and 90 days. The experimental results show that w/b has a significant effect on the drying shrinkage of the ECC mixtures. Drying shrinkage is remarkably reduced with a decrease in the w/b. The results also showed that drying shrinkage of the composites is considerably reduced when POFA is used in the matrix. The measured drying shrinkage strain at 90 days is only 920×10-6 µe to 1216×10-6 µe for ECC mixtures with high POFA content. The shrinkage strain of the ECC mixtures without POFA at 90 days is nearly 1597×10-6 µe to 1910×10-6 µe.

Nurdeen M. Altwair

Papers

Flexural performance of green engineered cementitious composites containing high volume of palm oil fuel ash.

Strength Activity Index and Microstructural Characteristics of Treated Palm Oil Fuel Ash

Characteristics of Treated Palm Oil Fuel Ash and its Effects on Properties of High Strength Concrete

Influence of treated palm oil fuel ash on compressive properties and chloride resistance of engineered cementitious composites

Shrinkage Characteristics of Green Engineered Cementitious Composites with Varying Palm Oil Fuel Ash Contents and Water-Binder Ratios