Recycling of Olive Pomace Bottom Ash (by-Product of the Clay Brick Industry) for Manufacturing Sustainable Fired Clay Bricks

Abstract

The present work investigates the effect of using olive pomace bottom ash, the by-product of the clay brick industry, as an additive in the manufacture of fired clay bricks. Furthermore, it aims to improve the properties of clay bricks by using naturally available materials and also to develop an innovative way of recycling the waste resulting from the brick firing process. Olive pomace bottom ash was added to clay with multiple proportions (0%, 5%, 10%, 15%, and 20%) by weight. Bricks were molded by compression at 6.5 MPa, using a hydraulic brick press machine, and fired in an industrial scale furnace. The physicochemical, mineral, and geotechnical properties of raw materials were identified to study raw materials' effect on the final fired products' performance. The quality of fired specimens was determined by bulk density, linear shrinkage, water absorption, porosity, compressive strength, and thermal conductivity. In fact, samples with 5% olive pomace ash represent the highest compressive strength level, 11.5 MPa, compared to 9.65 MPa of reference samples. On the other hand, additions up to 20% increase the brick sample's porosity from 18.28% to 34% for the reference mixture and the brick incorporated with 20% of additive, respectively, and decrease the brick's bulk density from 1522 kg/m 3 to 1431 kg/m 3 for the reference mixture and the brick incorporated with 20% of additive, respectively. The incorporation of ash also improves the thermal conductivity of brick specimens. Expressly, thermal conductivity went from 0.41 W/m.K to 0.33 W/m.K for the reference mixture and the brick incorporated with 20% of additive, respectively, showing 37% of gain in thermal insulating properties of brick. Unfortunately, the capillary water absorption coefficient increases to 28% when 20% of additive is incorporated, which is not desired in the properties of construction materials. ASTMC67-07a standards: 2003, recommend water absorption level less than 17% for bricks with moderate weathering resistance. It was concluded that the addition of olive pomace bottom ash should not exceed 10% since it can be helpful in fired clay brick production based on standards requirements, leading to remarkable ecological gains without a loss of brick's performances.

Mechanical and Thermal Properties of Goulmima’s Earth Bricks

“…This might be the result of CPS breaking down, as it contains some organic material that burns when it is fired [18]. In accordance to the European Standard [29], The compressive strength outcomes for all bricks (excluding S.20) meet the necessary minimum threshold of 7 MPa, consistent with the conclusions drawn from previous literature [26][27][28][29][30].…”

“…The compressive strength test is essential for assessing the quality of shaped bricks [10,26]. The compaction resistance test results are displayed in Fig.…”

“…As a result, the compressive strength decreases below this rate. A significant amount of silica in the CPS used in this study may have contributed to the geopolymerization process, which forms a compact and strong geopolymer by hardening and forming a viscous cementitious slurry from aluminate and silicate [26][27][28]. However, it is best to avoid adding a lot of CPS as this can reduce the bricks' compressive strength.…”

Physico-chemical, mineralogical, and technological characterization of stabilized clay bricks for restoration of Kasbah Ait Benhadou- Ouarzazate (south-east of Morocco)

“…Compressive strength is one of the most important tests to be able to evaluate the quality, and the suitability of the clayey materials for load bearing walls [40,41].…”

The Use of Expanded Polystyrene and Olive Stones in the Manufacture of Lightweight Bricks: Evaluation of Their Properties and Durability

“…Another olive oil waste, pomace, has been studied a little more extensively as an additive in the production of lightweight bricks [ 17 ]. Several other papers have been published about the use of other wastes, such as olive leaves and olive branches [ 18 ], wastewater from olive oil extraction [ 19 ], olive stones [ 20 , 21 ] and pomace ashes [ 22 , 23 ]. Spain is the world’s leading producer of olive oil, and the region with the largest cultivated area is Andalusia.…”