Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : lightweight concrete

Influence of Foaming Agent Type on The Behavior of Foamed Concrete

Ruqaya F. Hamada; Awham M. Hameed

Engineering and Technology Journal, 2021, Volume 39, Issue 1B, Pages 80-88
DOI: 10.30684/etj.v39i1B.1805

In this work the desired aim is to study the effect of two various sorts of a foaming agents on the properties of foamed concrete to obtain high quality with a target density is nearly 1600 kg/m3. The standard samples were designed by employing two types of foam agent (FA), the first one is commercially named (EABSSOC foam agent, FA) while the second is the foam of detergent liquid (D) which known (Fairy). The results showed that the FA sample records the lower bulk density compared to the other types. The perfect mix which involved 1wt.% of (D) had higher values of the compressive strength 20.25MPa, 16.32MPa of the curing in water and air respectively and flexural strength (F.S) values were 6.89MPa,4.47MPa of the cured samples in (air, water) for various durations (7,14 and 28) days compared to the samples that contained 1and 0.8wt. % of FA. The obtained compressive strengths were 5.1MPa, 4.3MPa while the flexural strengths were 2.74MPa, 2.9MPa for the samples contained 1wt. %foam agent (FA) after the curing into water and air at the same duration. It is obvious that the addition of foam to the cement mortar paste imparts great characteristics as lightweight with flowability. These properties and others make it suitable for some applications, for example, a decrease of the dead load from the structure, thermal and acoustic insulating and use it in non-structural sections such as a wall.

Experimental Investigation of the Production of Sustainable Lightweight Concrete

Mouhammed J. Lafta

Engineering and Technology Journal, 2020, Volume 38, Issue 11, Pages 1652-1665
DOI: 10.30684/etj.v38i11A.1621

An experimental study on four types of coarse aggregate was conducted to produce lightweight concrete. These four types are namely; white limestone, red limestone, clay brick fragments, and pumice. Ordinary Portland cement was used for all examined mixes. Water to cement ratio (w/c) was modified according to the effect of coarse aggregate type on the workability of the resulted concrete for each mix. The reference concrete mix, which is normal concrete, water to cement ratio used was (0.5). The investigated characteristics for all concrete mixes were workability, compressive strength, dry density, absorption, and thermal conductivity. Results indicated that the aggregate type significantly affects most of the properties of lightweight concrete mixes such as workability, density, and thermal insulation for all tested types of concrete. All investigated specimens indicated improvement in terms of density, workability, and thermal conductivity when compared to the reference concrete mix. Yet, it was derived from the testing results that using pumice in lightweight concrete production is the optimum option among the other examined types. When compared to normal concrete, this type of lightweight concrete showed a 41% decrease in dry density, nearly 72.54% decrease in thermal conductivity, and about 12% increase in workability. However, it is vital to notice that due to the low compressive strength and the relatively high absorption capability for all the examined types of lightweight concrete, it is suggested to use these types of concrete for non-structural walls that are not subjected to or exposed to high humidity.

Production of Lightweight Concrete by Using Construction Lightweight Wastes

Huda S. Abed

Engineering and Technology Journal, 2019, Volume 37, Issue 1A, Pages 12-19
DOI: 10.30684/etj.37.1A.3

This research covers the use of cellular lightweight concrete waste as recycled coarse aggregates to produce lightweight concrete. Various volume fractions of coarse aggregate (35%, 50%, and 75%) were used. The specimens were tested for compressive strength and density at age of 28-days. The compressive strengths for the resulting lightweight concrete with a density of (2131, 1826 and 1630) kg/m3 were (24, 22.6 and 11.5) MPa, respectively. In addition, silica fume was utilized as a constant replacement ratio 6% of cement weight for mixes lightweight aggregate to enhance the compressive strength of such concrete.

Mechanical Properties of Fiberous High Performance Lightweight Aggregate Concrete

H.K. Ahmed; W.I. Khalil; M.D. Subhi

Engineering and Technology Journal, 2017, Volume 35, Issue 3, Pages 229-238

Structural lightweight aggregate concrete solves weight and durability problems in buildings and structures. Recent advanced in material technology have accelerated the development of high performance concrete using lightweight aggregate. The main objective of this research is to produce high performance lightweight aggregate concrete reinforced with polypropylene and to study the mechanical properties of this type. The effect of various factors such as type of fiber and volume fraction of fibers also has been investigated. The experimental work included the use of pumice as coarse and fine lightweight aggregate, superplasticizer and silica fume to produce high performance lightweight concrete. Several trial mixes were examined to determine the proper proportion of the concrete constituent. Three types of polypropylene with different volume fraction were used. The procedure also includes studying the compressive strength, splitting tensile strength, flexural strength and static modulus of elasticity. The test results shows that the addition of all types of polypropylene fiber results in significant improvement in most mechanical properties compared with reference concrete specimens at different ages except compressive strength it was improved at Vf =0.25% and decrease at Vf =0.75%.

Effect of Shear Span-Depth Ratio on Shear Strength of Porcelanite Lightweight Aggregate Reinforced Concrete Deep Beams Strengthened by Externally Bonded CFRP Strips

K.F. Sarsam; N.A.M. Al-Bayati; A.S. Mohammed

Engineering and Technology Journal, 2017, Volume 35, Issue 3, Pages 267-275

This paper presents an experimental investigation of structural behaviour of reinforced concrete deep beams strengthened in shear by CFRP strips. The experimental program consisted of fabricating, casting and testing of nine identical porcelainte lightweight aggregate reinforced concrete deep beams. Three of the tested deep beams were unstrenghtened to serve as reference beams, while the remaining beams were tested after being strengthened using CFRP strips in two different orientations (vertical and horizontal). The locally available natural porcelanite aggregate is used to produce lightweight aggregate concrete. The beams were designed to satisfy the requirements of ACI 318M- 14 building code. In order to insure shear failure modes, adequate flexural steel reinforcement were provided. Effect of three different values of shear span to effective depth ratio (a/d =1.0, 0.8, 1.2) were selected. All beams have been tested as a simply supported beams subjected to two concentrated points loading. The beam specimens were tested up to failure under monotonic loads. The experimental work showed that the failure load increases as the shear span to effective depth ratio deceases. As the shear span to effective depth ratio decreased from 1.0 to 0.8, the percentage of increase in the ultimate load was about 24%. In addition, the diagonal compression strut crack of unstrenghtened control beams was changed to several diagonal cracks at mid depth within the shear span of the strengthened beams and exhibited more ductile failure mode.

A Comparative Study of Thermal Insulations and Physical Properties of Lightweight Concrete Using Some Raw Materials

Sanaa A. Hafid; Amenah E. Mohammed Ridha

Engineering and Technology Journal, 2016, Volume 34, Issue 4, Pages 470-478

In this work, no-fine lightweight concrete was produced by using crushed bricks, thermostone as coarse aggregates to produce lightweight concrete. For both, superplasticizers were added to the mixture, the specimens were then cured in water for (7, 28, 60) days respectively.
Compressive strength determine the mechanical properties, Physical properties of these concrete types were examined through thermal conductivity and fresh density. The compressive strength test showed that the compressive strength of the concrete was about (8-15.7) N/mm2 by
using natural gravel aggregate, (4.8-8.1) N/mm2 by using crushed bricks, and (3.14-5.4) N/mm2 by using thermostone aggregate. After 28 days, the thermal conductivity were (0.58),(0.41),(0.26) W/m.k, for the natural gravel ,crushed bricks and thermostone concrete.
Besides; these concrete types are characterized by their low cost, environmentally friendly,high production rate, fire resistance, thermal insulation and light weight.