Production Of Paving Blocks Research Articles

Reducing Cement Contents of Paving Blocks by Using Mineral Waste and by-Product Materials

AbstractIn the production of conventional paving blocks, it is usual to use a minimum of 210 kg/m3 of cement. However, when portland cement is produced, it impacts negatively on the environment due to carbon dioxide emissions. Therefore, this paper investigates the use of waste and by-product materials, such as run-of-station ash (ROSA), basic oxygen slag (BOS), ground granulated blast-furnace slag (GGBS), plasterboard gypsum (PG), and cement bypass dust (BPD) to reduce the amount of cement in paving blocks. The combinations of binary and ternary blends in different mixes are considered. Tensile strength, skid/slip and freeze/thaw resistance of paving blocks, verified that a cementitious mix containing ROSA up to 60%, GGBS up to 55%, BPD up to 25%, and plasterboard gypsum PG up to 5% by weight can replace portland cement without having any substantial impact on the strength or durability of the blocks. XRD and XRF tests of selected mixes have been presented and discussed. Concrete blocks prepared with OP...

Use of recycled CRT funnel glass as fine aggregate in dry-mixed concrete paving blocks

Abstract This paper investigates the feasibility of using recycled glass derived from discarded cathode ray tube (CRT) glass as an alternate fine aggregate for the production of dry-mixed concrete paving blocks. The recycled CRT funnel glass used had been acid treated and regarded as a non hazardous material based on the regulatory thresholds of the Toxicity Characteristic Leaching Procedure (TCLP). Two series of concrete paving blocks were prepared, one with and one without the use of coarse aggregate. Additionally, TiO2, a photo-catalyst was added to the surface layer of the blocks during the fabrication process to effect photo-catalytic reaction for the removal of an air pollutant, nitrogen oxide (NO). For each series, the CRT glass was used to replace the fine aggregate by volume at different ratios. Their physical, mechanical and durability properties, lead leachability, and photocatalytic air purifier performance were studied. The results show that the use of up to 100% CRT funnel glass as fine aggregate in concrete paving blocks not only have satisfactory levels in compressive strength (>45 MPa) and ASR expansion (

Use of Coal Waste as Fine Aggregates in Concrete Paving Blocks

The aim of this work was to study the use of coal waste to produce concrete paving blocks. The methodology considered the following steps: sampling of a coal mining waste; gravity separation of the fraction with specific gravity between 2.4 and 2.8; comminution of the material and particle size analysis; technological characterization of the material and the production of concrete paving blocks. The results showed that the coal waste considered in this work can be used to replace conventional sand as a fine aggregate for concrete paving blocks. This practice can collaborate in a cleaner coal production.

Production of concrete paving blocks (CPB) utilising electroplating residues – evaluation of mechanical and micro‐structural properties

AbstractThe objective of this study was to use electroplating waste [blasting dust (BD) and electroplating sludge] for the production of concrete paving blocks (CPBs) by means of the solidification/stabilisation technique and to characterise the mechanical and micro‐structural properties of CPBs. Granulometric tests showed that electroplating residues have a size range that allows their use as aggregates. Blocks were produced with compositions of 5, 10, 15, 20 and 25% BD and electroplating sludge, and reference blocks (REF) were produced without the addition of residues. Blocks were cured for 7, 14, 28, 60 or 90 days. The blocks produced with 5%, 10% and 15% BD had compression resistances at 28 days of 42.60 MPa, 37.57 MPa and 35.6 MPa, respectively, all of which are above the Brazilian limits for paved areas to be used by light vehicles (35 MPa). In contrast, the specimens produced with electroplating sludge behaved differently, probably due to their water/agglomerate ratio and the limited interaction of the cement matrix with the aggregate, which influenced the observed compression resistance values. Only the blocks manufactured with 5% electroplating sludge showed resistance values above the limit established by Brazilian standards (35.43 MPa), but the values were inferior to those of the reference block (37.35 MPa). Therefore, the characteristics of the electroplating residues (BD and electroplating sludge) are acceptable as raw materials in civil construction. The solidification/stabilisation technique also appeared to be quite promising for the incorporation of electroplating residues into cement matrix for the fabrication of CPBs. © 2012 Canadian Society for Chemical Engineering

Effects of compaction method and rubber content on the properties of concrete paving blocks

A wide variety of recycled waste has been successfully used in the production of concrete paving blocks. It is known that the mechanical properties of these concrete products tend to be inconsistent, which is understandable in view of the range of mix designs as well as the variety of materials and compaction methods that were adopted in the production. In this study, recycled waste tyre (crumb rubber) was used to replace sand by volume at the level of 0%, 10%, 20% and 30% in order to investigate how the soft rubber particles behave under plant-machine compaction method during the production of rubberized concrete paving blocks (RCPB). In the hardened stage, the physical properties as well as mechanical properties of RCPB including density, compressive strength, bending strength and skid resistance were studied. The results showed that as a small proportion (∼10%) of soft rubber particles was included in the mixture, the particles easily distorted and filled the voids between the solid particles. This filling mechanism reduced the porosity of concrete mixtures and effectively developed an adequate adhesion between the particles, resulting in higher gain in strengths. On the contrary, as the rubber ratio increased more than 10%, which the deformability is more predominant than the filling mechanism, this results in higher total stress concentrations and rebound stress of rubber particles, thus, increasing the porosity and micro-cracks, resulting in loss in strengths. Nevertheless, the presence of rubber in concrete did not demonstrate brittle failure, but rather a ductile which had an ability to withstand post-failure loads. In comparison, the mechanical properties of plant-made RCPB performed better than that of corresponding manually-made RCPB. Therefore, plant-compaction method is recommended for future RCPB production and crumb rubber content used to replace sand by volume should be kept at or less than 10%.

Properties of concrete paving blocks made with waste marble

Marble industry produces large amounts of waste marble – what causes environmental problems. In paving blocks based on two cement types we have partly replaced aggregate with waste marble. Physical and mechanical tests were performed on blocks so produced. The cement type turns out to be an important factor. Mechanical strength decreases with increasing marble content while freeze-thaw durability and abrasive wear resistance increase. Waste marble is well usable instead of the usual aggregate in the concrete paving block production.

Production of ‘green’ concrete using red gypsum and waste

The main cost incurred in the production of concrete paving blocks is the cost of the cement-based binders. In addition, there is the environmental cost of quarrying and processing of these primary materials. Gypsum-based industrial by-products have been identified as alternative sources of cement. These materials have little or no production cost and their reuse negates the need for disposal, offering a more sustainable material for the production of paving blocks. Laboratory trials have investigated the properties of red gypsum, derived as a coproduct associated with titanium dioxide manufacture, mixed with pulverised-fuel ash, ground granulated blastfurnace slag, lime and basic steel slag. An assessment of samples was made using unconfined compressive strength after 28 days curing. It was found that a red gypsum ground granulated blastfurnace slag mix achieved the highest unconfined compressive strength (up to 39 MPa) and was selected for further investigation. Two binders, composed primarily of red gypsum and ground granulated blastfurnace slag, were mixed with sand and pea gravel to make 100 mm concrete cubes and compared with Portland cement for uniaxial compressive strength, stiffness and workability. The red gypsum-based binder compared favourably with Portland cement, indicating that there is potential to integrate red gypsum into concrete block mixes.

Using recycled construction waste as aggregates for paving blocks

The use of paving blocks made from recycled materials, in particular recycled concrete aggregate derived from demolition waste streams, has gained a wider acceptance in Hong Kong. However, the use of wastes generated from building activities is generally considered unsuitable for this application. This paper describes a study on the use of construction waste in the production of paving blocks for residential applications. Construction waste (concrete rubble, clay brick, low-quality and high-quality ceramic tiles, lightweight blocks, concrete masonry blocks, timber and bamboo) was crushed into fine aggregate prior to production of the paving blocks. The density, compressive strength, breaking load, modulus of rupture and water absorption were measured for these laboratory-prepared paving blocks. The results were compared with those from control paving blocks fabricated using river sand. The influence of iron oxide pigment on the properties of the paving blocks was determined. The weathering properties of the paving blocks prepared with recycled materials were also assessed. The results indicate that it is feasible to recycle building site waste for use in paving block production, but the inclusion of lightweight materials should be avoided or limited. Based on the findings, limits of different waste materials allowed in paving block production are recommended.