Production Of Lightweight Concrete Research Articles

Mechanical properties of EPS lightweight concrete

The aim of this study was to investigate the effects of expanded polystyrene aggregate size, matrix strength and polypropylene fibre addition on the strength of lightweight concrete. Three types of expanded polystyrene beads with 1·0, 2·5 and 6·3 mm diameter were added to a high-strength matrix to produce lightweight concrete. Fine silica fume and polypropylene fibres were used to improve material properties. Lightweight expanded polystyrene concretes with different matrix strengths were investigated for compressive and splitting tensile strength. The expanded polystyrene concrete with small expanded polystyrene beads showed higher compressive strengths and the increase was more pronounced in low-density concrete than high-density concrete. The matrix strength was also observed to affect the particle size effect of expanded polystyrene beads on the compressive strength of concrete. The increase in compressive strength with the decrease of expanded polystyrene bead size was more pronounced in the low-strength matrix. In addition, polypropylene fibres significantly improved the strength of expanded polystyrene concrete, with the 28-day compressive and splitting tensile strengths of expanded polystyrene concrete being up to 43 and 44% higher than those of reference concrete.

Mixture Design Development and Performance Verification of Structural Lightweight Pumice Aggregate Concrete

Naturally occurring lightweight volcanic pumice aggregate was used for the development of structural lightweight concrete. The primary aim of the investigation was to reduce both the economic costs and the negative environmental effects that are typically associated with production of conventional lightweight concrete containing artificially produced aggregates by taking advantage of New Zealand’s abundant pumice resources. Mixture designs were developed for concrete containing both partially saturated and fully saturated pumice aggregates, achieving compressive strengths up to 40 MPa while maintaining unit weights below 1,850 kg/m3. A vacuum saturation system was developed to completely saturate the normally partially saturated aggregates, which was necessary to avoid a loss of workability and to alleviate complications with mix-water calculations that occurred for concrete containing partially saturated pumice aggregates. Experimental investigations into the bond strength and shear strength of pumice concrete were also conducted. The results showed that the mixtures developed outperformed both the bond and shear strength requirements for structural lightweight concrete of the New Zealand Concrete Structures Standard NZS 3101:2006. The research presented demonstrates the effective and innovative use of New Zealand’s abundant resources of naturally occurring pumice aggregates for producing structural lightweight concretes that meet the requirements of New Zealand concrete structures standards.

Flexural and time-dependent performance of palm shell aggregate concrete beam

The use of Oil Palm Shell (OPS) as coarse aggregate is a cost-effective approach in the production of structural lightweight concrete. This paper investigates the flexural and long-term deflection performance of palm shell aggregate concrete beams. Both experimental and theoretical studies are carried out on 1.5 m long beams to investigate the structural performance. A total of nine beams having different mix ratios are tested in the laboratory under different service loading condition. Factors affecting the short and long-term deflections of palm shell aggregate concrete beams are highlighted in this paper. The experimental results are compared with the theoretical results. From the experimental investigation and theoretical analysis, it is concluded that cracked section under sustained loading showed larger deflection compared to that of uncracked section. The theoretical approach can give conservative estimate of the deflection provided the factors affecting the long-term performance of palm shell concrete beams are addressed.

Optimization of properties of fly ash aggregates for high-strength lightweight concrete production

The optimization of properties of lightweight fly ash aggregates for suitability in high-strength lightweight fly ash concrete production was investigated using response surface methodology (RSM). Design-Expert software was used to establish the design matrix and to analyze the experimental data. The relationships between the sintering parameters (temperature, binder content and binder type) and experimentally obtained three responses (specific gravity, water absorption and crushing strength) were established. Also, the optimization capabilities in Design-Expert software were used to optimize the sintering process. Historical data design technique under RSM was performed to optimize the input parameter interactions which showed the best conditions for preparation of fly ash pellets. According to the obtained results, the developed models are statistically accurate and can be used for further analysis. The experimental values agreed with the predicted ones, thus indicating suitability of the model employed and the success of RSM in optimizing the sintering conditions.

Processing Lightweight Aggregate to produce Lightweight Concrete

The modern techniques development used in the production of concrete led to the emergence of types of concrete with different densities compared to normal concrete . This research aimed manufacturing types of lightweight aggregate (coarse and fine) and then the production of lightweight concrete blocks with a good thermal insulation , by using available locally materials . Two types of lightweight aggregate , have been produced by using two methods of manufacturing , first type , where AL-Hadbaa aggregate , produced from Clay , which is on the edge of the Tigris river in Mosul , using 50% Clay and 50% silt , the density obtained about 860 Kg/m3 . The second AL-Rabean aggregate , was the adoption of natural laminated Clay which is located in Nineveh province , in very large quantities , it's mineralization is Montmurlite and kaolinite , density obtained was 750 Kg/m3 , this type did not produce in Iraq and which it's manufactured method simple and economic . The standard tests have been made and were adopted in the production of concrete blocks , lightweight concrete block produced from AL-Hadbaa aggregate , used in bearing walls , have 28 – day compressive strength 15.33 N/mm2 and density about 1770 Kg/m3 . The AL-Rabeaan aggregate used to product concrete block for the purposes of thermal insulation , it's thermal conductivity coefficient was 0.55 W/m.kcal and have a density 1640 Kg/m3 . Keywords : Clay , lightweight aggregate , concrete block

Oil palm shell as a lightweight aggregate for production high strength lightweight concrete

In Malaysia, oil palm shell (OPS) is an agricultural solid waste originating from the palm oil industry. In this investigation old OPS was used for production of high strength lightweight concrete (HSLC). The density, air content, workability, cube compressive strength and water absorption were measured. The effect of five types of curing conditions on 28-day compressive strength was studied. The test results showed that by incorporating limestone powder and without it, it is possible to produce the OPS concretes with 28-day compressive strength of about 43–48 MPa and dry density of about 1870–1990 kg/m 3. The compressive strength of OPS HSLC is sensitive to the lack of curing. The water absorption of these concretes is in the range of good concretes.

Producing Light Weight Concrete Using Pumice and Mineral Aggregates and Comparing the Curing Process of Autoclave with Saturated Condition

Producing Light Weight Concrete Using Pumice and Mineral Aggregates and Comparing the Curing Process of Autoclave with Saturated Condition

Pelletisation of fly ashes as a lightweight aggregate

This study investigated the use of solid waste fly ash in the production of lightweight concrete. Fly ash is an industrial waste obtained from the coal-fired thermal generating power plant and it is used in the production of additive construction materials. In Turkey more than 15 million tonnes of fly ash is produced each year, but only a small amount is utilised. The industrial waste fly ashes used in this study came from the power plant at Iskenderun Sugozu, Cayirhan, Tuncbilek and Seyitomer. Lightweight aggregate manufactured from the fly ash and Na-bentonite was used in a pelletisation process. The lightweight concrete manufactured from fly ash aggregate was analysed in terms of the slump and density of fresh concrete and the density, compressive strength and tensile splitting strength of hardened concrete. In the present study, the effects of fly ash aggregates from different power plant when used for lightweight concrete production purposes were investigated and the results obtained were quite satisfactory for the related design requirements.

An investigation on the use of shredded waste PET bottles as aggregate in lightweight concrete

In this work, the utilization of shredded waste Poly-ethylene Terephthalate (PET) bottle granules as a lightweight aggregate in mortar was investigated. Investigation was carried out on two groups of mortar samples, one made with only PET aggregates and, second made with PET and sand aggregates together. Additionally, blast-furnace slag was also used as the replacement of cement on mass basis at the replacement ratio of 50% to reduce the amount of cement used and provide savings. The water-binder (w/b) ratio and PET-binder (PET/b) ratio used in the mixtures were 0.45 and 0.50, respectively. The size of shredded PET granules used in the preparation of mortar mixtures were between 0 and 4 mm. The results of the laboratory study and testing carried out showed that mortar containing only PET aggregate, mortar containing PET and sand aggregate, and mortars modified with slag as cement replacement can be drop into structural lightweight concrete category in terms of unit weight and strength properties. Therefore, it was concluded that there is a potential for the use of shredded waste PET granules as aggregate in the production of structural lightweight concrete. The use of shredded waste PET granules due to its low unit weight reduces the unit weight of concrete which results in a reduction in the death weight of a structural concrete member of a building. Reduction in the death weight of a building will help to reduce the seismic risk of the building since the earthquake forces linearly dependent on the dead-weight. Furthermore, it was also concluded that the use of industrial wastes such as PET granules and blast-furnace slag in concrete provides some advantages, i.e., reduction in the use of natural resources, disposal of wastes, prevention of environmental pollution, and energy saving.

A novel material for lightweight concrete production

Abstract This paper presents the results of an experimental study on the effects of using recycled waste expanded polystyrene foam (EPS), as a potential aggregate in lightweight concrete. In this study, thermally modified waste EPS foams have been used as aggregate. Modified waste expanded polystyrene aggregates (MEPS) were obtained by heat treatment method by keeping waste EPS foams in a hot air oven at 130 °C for 15 min. Effects of MEPS aggregate on several properties of concrete were investigated. For this purpose, six series of concrete samples were prepared. MEPS aggregate was used as a replacement of natural aggregate, at the levels of 0%, 25%, 50%, 75%, and 100% by volume. The density of MEPS is much less than that of natural aggregate; MEPS concrete becomes a lightweight concrete with a density of about 900–1700 kg/m3. The 28-d compressive strengths of MEPS concrete range from 12.58 MPa to 23.34 MPa, which satisfies the strength requirement of semi-structural lightweight concrete.

Studies on some factors affecting CO 2 curing of lightweight concrete products

This paper deals with the effects of several factors, such as CO 2 pressure, curing time, water-to-cement ratio and continued curing after CO 2 curing on temperature profiles, CO 2 curing degree and strength of concrete. Results indicated that the accelerated reactions between CO 2 and cement minerals happen mainly during the first 15 min regardless of CO 2 pressure and pre-conditioning environment. CO 2 curing degree and strength increased as the CO 2 pressure and curing time increased. The concrete specimens should have a water-to-cement ratio greater than certain value so as to facilitate the moulding of concrete products and to achieve a high CO 2 curing degree. CO 2 cured specimens will continue to gain strength due to the hydration of cement minerals unreacted during the CO 2 curing if the specimens are kept in moist environment.

Proportioning and characterization of lightweight concrete mixtures made with rigid polyurethane foam wastes

This paper presents the results of an experimental study concerning the incorporation of polyurethane (PUR) foam wastes into cementitious mixtures in order to produce lightweight concrete. A semi-empirical method is first proposed to predict the density of fresh PUR foam-based concrete mixtures. Seven concrete mixtures containing various PUR foam volume fractions (from 13.1% to 33.7%), and two reference concrete mixtures (without PUR foam) were prepared and characterized. In particular, their thermal and mechanical properties were determined. This permitted to quantify the influence of the PUR foam volume fraction on these parameters. Some specimens were maintained under water during 28 days, while the others were dried in air. The PUR-foam concrete thermal conductivity and compressive strength are, respectively, 2–7 times and 2–17 times lower than those of the reference mixture, depending on the volume fraction of PUR foam and on the curing conditions. Besides, the use of PUR foam in concrete implies a strong increase in the drying shrinkage and in the mass loss during the first seven days. These results can be related to the high porosity and the weak compressive strength of alveolar polyurethane.

Use of zeolite-rich rocks and waste materials for the production of structural lightweight concretes

This paper aims at testing the use of mixtures constituted by natural zeolitized products and SiC-bearing industrial wastes (sludge deriving from polishing of porcelain stoneware tiles, hereafter DPM) for the production of lightweight expanded aggregates as constituents of structural and/or thermo-insulating lightweight concretes. Two commercial products have been used as zeolite natural source: Cab70 (Yellow facies of Campanian Ignimbrite) and IZclino (Turkish clinoptilolite-rich epiclastite). Different amounts of a calcareous material (Pozzano limestones — hereafter CP) from the Sorrento peninsula (Naples — Italy) were also added to a Cab70–DPM mixture. All raw materials were characterized by means of mineralogical (XRPD) and chemical (XRF) analyses. All the products and mixtures were tested from a technological point of view by means of fusibility and firing tests in order to evaluate the expanding properties. It was evidenced that the expansion of the mixture was deeply depending on the occurrence of SiC in the industrial waste. The addition of CP (10 wt.%) to the mixtures accounts for an even increased expansion, though this is accompanied by a worsening of the mechanical features of the material. These results along with literature data allowed to select 3 mixtures (70% Cab70–30% DPM, 70% IZclino–30% DPM, 60% Cab70–30% DPM–10% CP) and each of them was used for the preparation of 5 l of lightweight aggregates afterward employed for the manufacture of lightweight concretes. It was remarked that natural zeolitized materials mixed with DPM (30 wt.%) can provide lightweight aggregates with densities ranging between 0.8 and 1.0 g/cm 3 suitable for the preparation of structural lightweight concretes. The addition to the mixture of CP (10 wt.%) produces less dense aggregates (0.6–0.7 g/cm 3) potentially useful for the manufacture of thermo insulating lightweight concretes.

Reuse of thermosetting plastic waste for lightweight concrete

This paper presents the utilization of thermosetting plastic as an admixture in the mix proportion of lightweight concrete. Since this type of plastic cannot be melted in the recycling process, its waste is expected to be more valuable by using as an admixture for the production of non-structural lightweight concrete. Experimental tests for the variation of mix proportion were carried out to determine the suitable proportion to achieve the required properties of lightweight concrete, which are: low dry density and acceptable compressive strength. The mix design in this research is the proportion of plastic, sand, water-cement ratio, aluminum powder, and lignite fly ash. The experimental results show that the plastic not only leads to a low dry density concrete, but also a low strength. It was found that the ratio of cement, sand, fly ash, and plastic equal to 1.0:0.8:0.3:0.9 is an appropriate mix proportion. The results of compressive strength and dry density are 4.14N/mm2 and 1395 kg/m3, respectively. This type of concrete meets most of the requirements for non-load-bearing lightweight concrete according to ASTM C129 Type II standard.

Radiological safety aspects of utilizing coal ashes for production of lightweight concrete

The present paper reports the results of experiments to develop environmentally and economically friendly structural lightweight concretes utilizing coal ashes and other waste materials. The product complies with national and international regulations setting limits on the activity concentration of natural radioisotopes in building products. The utilization of coal ashes in the building industry carries (in addition to its economic advantages) a fringe environmental benefit. This utilization reduces the potential damage to the environment caused by the radioactivity in the combustion by-products (the ashes) stored in piles and ponds near the power stations prior to their disposal. The study deals with the radiological characteristics of coal ashes and lightweight concretes based on these ashes. The ashes are generated at Israel’s power stations from coal supplied from different sources in South Africa, Columbia and Indonesia.

Diyatomitin Hafif Beton Üretiminde Kullanilmasi

Use of Diatomite in the Production of Lightweight Concrete The use of diatomite found in Turkey and in Afyonkarahisar Region has not been evaluated in the production of lightweight concrete as aggregate up to now. In the study, physical and mechanical properties of lightweight concrete manufactured with diatomite aggregates have been investigated. Cement Content of the concretes have been changed between 250 and 400 kg/m 3 ; but the water/cement ratios were kept constant as 0,15. Compressive strength, thermal conductivity, water absorption, bulk density, ultrasonic pulse velocity and apparent porosity of the concrete have been determined. Microstructures of the specimens were also studied by SEM. According to the experimental test results obtained, diatomite aggregates in the production of lightweight concretes can be satisfactorily used.

Properties of autoclaved lightweight aggregate concrete

Many researches have been carried out on production and properties of pre-cast concretes. Currently, most of them have focused on normal concrete, and are unable to completely represent the behavior of lightweight concrete (LWC). In this study, physical and mechanical properties of LWC produced with diatomite and pumice lightweight aggregates after autoclave curing were investigated. In the production of LWC, 0–4 mm maximum sizes of aggregates were used. Cement content and water/cement ratio were kept at 300 kg/m 3 and 0.20, respectively. The specimens were prepared in ∅50×100 mm cylindrical shape, and after 24 h of demoulding exposed to autoclave curing for 2, 4, 6, 8 and 10 h. Besides, two different cures were applied on the specimens as in water and in air at 20 °C±2, respectively. At the end of autoclaving and environmental cure, compressive strength in 7, 28 and 590 d, unit weight, specific porosity, thermal conductivity and water absorption were tested. Also, microstructures of LWC produced with diatomite and pumice aggregate were investigated. As a result, it is concluded that by autoclaving of specimens in 8–10 h, especially, compressive strength of specimens have increased 75% of strength of 28 aged specimens cured in water.

Production of lightweight concrete using incinerator bottom ash

The medium size fraction (14–40mm) of aged incinerator bottom ash (IBA) obtained from a major UK energy from waste (EfW) plant has been crushed to less than 5mm (CIBA) and thermally treated at 600°C (TCIBA6), 700°C (TCIBA7), 800°C (TCIBA8) and 900°C (TCIBA9). Thermal treatment reduced the organic carbon content and increased the amount of wollastonite (CaSiO3), mayenite (Ca12Al14O33) and gehlenite (Ca2Al2SiO7). The crushed and thermally treated IBA has been mixed with Portland cement (PC) at different water/solid (w/s) ratios and with different proportions of PC and Ca(OH)2. The volume expansion during setting and bulk densities and compressive strengths were determined. Expansion occurred in all mixes contained IBA during curing. A lightweight material (density less than 1.8g/cm3) with 28day compressive strength of higher than 10MPa was prepared by mixing 20wt% PC with 80wt% TCIBA8 at w/s ratio of 0.20. The expansion and associated lightweight properties result from gas evolution during curing due to residual metallic Al in the IBA. The main crystalline hydration products in 28day cured samples were portlandite (Ca(OH)2), calcite (CaCO3) and calcium aluminate carbonate hydrates (Ca4Al2O6(CO3)0.5·12H2O and Ca8Al4O14CO2·24H2O).

Lightweight concrete made from oil palm shell (OPS): Structural bond and durability properties

The first part of this experimental program was to determine the structural bond properties of lightweight concrete incorporating solid waste oil palm shell (OPS) as coarse aggregate and also to compare its behaviour with other types of lightweight aggregate concretes. Other properties of OPS concrete namely the split tensile strength, modulus of rupture and modulus of elasticity were also determined. The structural bond properties were determined through pull-out test. The results showed that the experimental bond strength of OPS concrete was much higher than the design bond strength as stipulated by BS 8110. In general, the properties of OPS concrete compared well with that of other structural lightweight concretes and the results obtained encourage the use of OPS as aggregates for the production of structural lightweight concrete. The second part of the experimental program investigates the durability performance of OPS concrete through water permeability and water absorption tests.

Structural lightweight concrete based on coal ashes (containing undesirable radionuclides) and waste of stone quarries

Utilisation of coal combustion by-products (bottom ash and fly ash) generated at power stations and stone quarries waste (unprocessed crushed sand), for the production of lightweight concrete is being studied at the Research Authority of The College of Judea and Samaria (Ariel, Israel). One of the main contributions of this study is the manufacturing of ecologically friendly lightweight concrete using coal ashes containing different quantities of natural radionuclides. For this goal, a technology for the production of a ternary lightweight concrete based on the use of above-mentioned waste was developed. The conducive features of each material are used in an optimum manner that enables the production of an ecologically friendly concrete with desirable building characteristics. Bottom ash is used as a porous lightweight aggregate. A mixture of the fly ash with the cement forms a dense matrix, which compensates for the low strength of bottom ash particles. Unprocessed crushed sand is used as a diluting non-radioactive material, which reduces the radioactivity of the concrete to a safe level. It is used also to further increase the strength of the lightweight concrete. Based on laboratory and field studies, the technology that has been developed can be recommended for production of structural lightweight concrete, which complies with the requirements of present standards related to strength and density, as well as to radiological characteristics.