Light-transmitting lightweight concrete with waste pet aggregate

Abstract

The invention relates to light-transmitting lightweight concrete with waste PET aggregate obtained by replacing 50% of the volume of natural aggregate in concrete material that can be used in the construction sector with waste PET aggregate and incorporating optical fibers.

Description

[0001] LIGHT-TRANSMITTING LIGHTWEIGHT CONCRETE WITH WASTE PET AGGREGATE

[0002] TECHNICAL FIELD

[0003] The invention relates to a light-transmitting lightweight concrete with waste PET aggregate, obtained by replacing 50% by volume of natural aggregate in concrete material that can be used in the construction sector with waste PET aggregate and incorporating optical fibers.

[0004] BACKGROUND

[0005] One of the prior art works related to the invention is light-transmitting fiber optic semi-transparent concrete, with the application number 2008 / 09834. This product is obtained by arranging optical fibers between a concrete mixture consisting of cement, sand, and water. Since its unit weight is between 2-2.5 g / cm3, it is classified as normalweight concrete. The mixture does not contain waste PET or any other type of waste.

[0006] In the prior art, there are also products of two commercialized brands. The type called transparent concrete from these products is different from the technique of the invention subject to the application. In this type, the transparency feature is prioritized over its strength property. Optical fibers cut into small pieces are randomly distributed into the thin concrete mixture to obtain transparent concrete. The second product of these brands is in the prior art of the invention. Light-transmitting concrete is produced by placing specially shaped and regularly spaced light-transmitting plastic elements into the concrete. Natural aggregate is used in these products.

[0007] In the previous technique, there is no product in which waste PET aggregate is used in light-transmitting concretes. In the current light-transmitting concretes, transparency and aesthetic properties are considered rather than strength properties. Additionally, since fluid and void-free concrete is used, the unit weight of the product is high. Since no waste or recycled components are used, its cost is high.

[0008] Within the scope of our invention, light-transmitting lightweight concrete with waste PET aggregate with low unit weight and thermal conductivity value was obtained by using waste polyethylene terephthalate (PET) fragments as aggregate in the same amount by volume together with natural aggregates.

[0009] AIM OF THE INVENTION The aim of the invention is to develop a "light transmitting lightweight concrete with waste PET aggregate" where half of the aggregates forming the concrete by volume consists of waste PET fragments.

[0010] Since the unit weight of light-transmitting lightweight concrete with waste PET aggregate is lower compared to light-transmitting concrete with the same amount of aggregate, it allows the production of large-sized concrete elements. As it will bring less load to the structure, it can be used on many walls in the building. All interior walls can be produced from light-transmitting lightweight concrete with waste PET aggregate. Thus, natural lighting can be utilized throughout corridors and halls.

[0011] Light transmitting lightweight concrete components with waste PET aggregate that are lightweight, have high strength and low thermal conductivity meet the performance requirements expected from exterior wall elements. PET bottle waste, which has increasingly growing usage areas and requires very long periods to decompose in nature, causes major environmental pollution. Safe disposal of PET waste has become an important issue. By using waste PET as aggregate in lighttransmitting lightweight concrete production, recycling / reuse of large amounts of PET waste can be achieved, contributing to the economy and environmental protection.

[0012] LIST OF FIGURES

[0013] Figure 1 . General View of the Invention

[0014] Corresponding numbers are given in figures:

[0015] 1 . Optical fiber

[0016] 2. Lightweight concrete with waste PET aggregate

[0017] DETAILED DESCRIPTION OF THE INVENTION

[0018] The invention relates to a formulation of a lightweight concrete type (2) with recycled waste PET aggregate that is more efficient than conventional lightweight concrete in terms of mechanical properties, in addition to allowing light transmission.

[0019] The matrix used in the formulation of the concrete subject to the invention is lightweight concrete with waste PET aggregate (2) shown in Figure 1 , consisting of Portland cement, water, and superplasticizer additive. To exemplify the content of lighttransmitting lightweight concrete mixture with waste PET aggregate (2) by weight; it consists of 50% cement, 17.5% water, 1 % chemical additive, 21 % silica sand, and 10.5% waste PET aggregate. The amount of natural aggregate and PET aggregate used in the mixture is equal in volume.

[0020] Waste PET aggregates are used after transparent beverage bottle waste is washed, cleaned, crushed, and sieved. The maximum particle size of silica sand used for easy placement of concrete mixture between optical fibers is determined as 600 pm, and the maximum particle size of waste PET aggregate is determined as 2 mm.

[0021] Optical fibers (1 ) used in concrete are basically thin plastic fibers that direct light. The core material of single-fiber optical fiber (1 ) with 1 mm diameter is transparent polymethyl methacrylate (PMMA) with high refractive index, and the coating material is transparent fluorinated polymer with low refractive index. Since PMMA fiber is a flexible material, it is easy to shape and bend. This feature allows the production of lightweight concrete in different forms. Optical fibers are placed parallel to each other in the molds while the lightweight concrete mixture is fresh. Since optical fiber operates on the end-lighting principle, the end parts of the optical fiber material protruding from both ends of the hardened concrete are cleaned and cut, thus allowing light received from one end of the fiber and reflected through it to reach the other surface of the lightweight concrete.

[0022] In accordance with the above explanation, mechanical properties such as compressive and flexural strength of light-transmitting lightweight concrete with waste PET aggregate (2) are superior to existing lightweight concrete in addition to its light transmission property. The mentioned light-transmitting lightweight concrete with waste PET aggregate (2) can be used as wall panels in all kinds of exterior and interior spaces where daylight and artificial light are allowed to enter. Since the optical fiber (1 ) inside is resistant to impacts, chemical agents, and UV rays, it can be safely used in building envelopes and open space designs.

[0023] The production method of the light transmitting lightweight concrete with waste PET aggregate (2) subject to the mentioned invention is explained in detail below:

[0024] Steel molds of desired size are prepared by oiling. Optical fibers (1 ) with 1 mm diameter are cut approximately 2 mm shorter than the mold length. Two plywood boards with 1 mm diameter holes drilled at 7 mm intervals are placed opposite each other, and optical fibers (1 ) are passed through the holes. Plywood boards with optical fibers (1) are placed in steel molds, and optical fibers (1 ) are leaned against both ends of the mold in a taut manner. Cement, silica sand, waste PET aggregate, water, and plasticizer additive forming the lightweight concrete matrix are mixed. The water / cement ratio of the mixture is 35%, and the plasticizer / cement ratio is 2%. Since the distance between optical fibers (1 ) is small, the prepared mixture is of self-compacting concrete consistency.

[0025] The prepared concrete mixture is poured into the molds through the optical fibers (1 ), and the molds are vibrated during pouring to eliminate voids. After hardening under normal curing conditions for 24 hours, the concrete is removed from the molds, and the plywood boards at both ends are removed.

[0026] Since optical fiber (1) operates on the end-lighting principle, the end parts of the optical fiber (1) material protruding from both ends of the hardened concrete are cleaned and cut, thus allowing light received from one end of the fiber and reflected through it to reach the other surface of the lightweight concrete with waste PET aggregate (2).

[0027] Prismatic molds of 4x4x16 cm dimensions were used to determine the unit weight, flexural tensile strength, compressive strength, and water absorption values of the produced concrete. Prismatic molds of 7x7x3 cm were used to determine the light transmission level. Tests were performed on specimens kept under wet curing conditions for 28 days.

[0028] The light-transmitting lightweight concrete with waste PET aggregate (2) produced within the scope of the invention is classified as lightweight concrete due to its unit volume weight of 1 .8 g / cm3; it is a lightweight concrete with normal concrete strength properties with compressive strength of 37 MPa and flexural strength of 6 MPa. The water absorption rate is in the range of 18-20%. Due to the embedded optical fibers (1 ) having properties similar to fiber reinforcement, concrete shows ductile behavior under flexural loads, and after fracture, optical fibers (1 ) maintain structural integrity by preventing the lightweight concrete element from fragmenting.

[0029] In measurements made to determine the light transmittance of the specimen, when the specimen containing optical fibers (1 ) at 1.3% of the surface area was exposed to a light source of 3100 lux, the amount of transmitted light was 61 lux. Light transmittance value can be increased by increasing the optical fiber (1 ) diameter and / or the amount of optical fibers (1 ).

[0030] The invention has physical and mechanical properties that enable its use as panels in exterior and interior walls due to its higher compressive strength compared to other lightweight concrete, ductile fracture property, and containing waste PET aggregate that is unaffected by water and atmospheric conditions. In addition to the advantages of existing light-transmitting concrete, it is a product with potential for use in the construction sector as an environmentally friendly concrete that is lighter, has lower thermal conductivity, and can utilize large amounts of PET bottle waste thanks to the waste PET aggregate used. Light-transmitting lightweight concrete with waste PET aggregate (2) can be used in more application areas than traditional lightweight concrete in structural applications, building elements of spaces requiring lighting, for both functional and aesthetic purposes due to its ecological, economic, mechanical, and optical properties.

Claims

CLAIMS1. A light-transmitting lightweight concrete with waste PET aggregate (2) characterized by comprising waste PET aggregate in the same proportion by volume as natural aggregate in the mixture and containing optical fiber (1 ) that enables natural or artificial light on one surface of the produced lightweight concrete (2) to pass through to the other surface.

2. The light-transmitting lightweight concrete with waste PET aggregate (2) according to Claim 1 , characterized by comprising 50% cement, 17.5% water, 1 % chemical additive, 21 % silica sand, and 10.5% waste PET aggregate by weight.

3. The light transmitting lightweight concrete with waste PET aggregate (2) according to Claim 1 , characterized by the optical fiber (1 ) having a diameter of 1 mm.

4. The light transmitting lightweight concrete with waste PET aggregate (2) according to Claim 1 , characterized by comprising CEM I 42.5 R Portland Cement as binder, water, natural aggregate (silica sand), waste PET aggregate, polycarboxylic ether-based high water-reducing super plasticizer additive.

5. A production method of light transmitting lightweight concrete with waste PET aggregate (2) according to Claim 1 , characterized by comprising the steps below:- Passing optical fibers (1) with 1 mm diameter through holes drilled at 7 mm intervals, 1 mm in diameter, in two plywood boards with ends protruding,- Placing plywood boards holding optical fibers (1 ) taut at both ends of the oiled concrete mold,- Pouring the concrete mixture consisting of cement, water, chemical additive, natural aggregate (silica sand), and waste PET aggregate in a 1 :1 ratio by volume and mixed homogeneously through the optical fibers (1 ) into the mold,- Eliminating voids by vibration compaction during pouring of the mixture into the molds,- Removing the hardened concrete from the mold after keeping it in standard curing conditions for 24 hours,- Removing the plywood boards at both ends of the hardened concrete and cleaning and cutting the ends of optical fibers (1 ) protruding from the ends of the concrete to be flush with the concrete.

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