Advanced Materials Research Vols. 261-263

Abstract: The elastic modulus of cement paste is the key parameter for characterizing the mechanical response of concrete. In modern concrete technology, the admixtures are often used to enhance the performance of concrete. This paper introduces a nondestructive testing method to evaluate the dynamic elastic modulus of cement paste. Moreover, the effect of water-cement ratio and conventional admixtures on the dynamic elastic modulus of cement paste is investigated, in which three kinds of admixtures are taken into account including Viscosity Modifying Admixture (VMA), Silica Fume (SF), and Shrinkage-Reducing Admixture (SRA). The results from experimental investigation indicate that the dynamic elastic modulus of cement paste increases with decreasing water-cement ratio. The addition of SF increases the dynamic elastic modulus, however, the overdosage of VMA causes its reduction. SRA reduces the elastic modulus at early age without affecting the elastic modulus at later period.

Abstract: Steel reinforced concrete is generally used in houses structure elements. However bamboo strength properties similarly to the wood, make it an alternative concrete composite material. Load test were performed in two kinds of bamboo guadua concrete reinforced composite slabs. During the tests the slabs functioned as domestic roofing-flooring in standing houses, the slab systems tested were bamboo stem covered slab and stem free slab. Two different tests were designed to measure the deflection in the middle of the composite slab and along a single bamboo stem. In three different slab sizes and after replications, no deflection under the applied load was recorded. Therefore, bamboo composite slabs without steel reinforcing seem likely to be used in long lasting houses for middle and high class dwellings in Colombia.

Abstract: Bamboo is a typical natural building material, which is longitudinally reinforced by robust fibers. This present paper focuses on the three-point bending fracture behavior of bamboo across and along fiber lengths with dense fiber layer upward and downward. The three-point bending strength of bamboo across the fibers is about ten times higher than that along the bamboo fibers, and the value of three-point bending strength with dense fiber layer downward is higher than that with dense fiber layer upward. Based on the microstructure of the fracture surfaces and the loading curves, different fracture processes are concluded to explain the anisotropy of bamboo.

Abstract: The development of new alternative type of pozzolanics soil bricks using the locally available clay from Ratchaburi province were mixed with fly ash from Kanchanaburi province, where both source in western of Thailand, is the main purpose of this study. These are compared to the local clay cement bricks without the mixing of flyash in different proportions. In the present work, the physical properties of the specimens are presented namely, compressive strength, modulus of rupture, thermal conductivity and unit weight. Tests were also conducted to study the influence of time of curing on the increase in physical properties of the bricks. It was concluded that the addition of fly ash reduces the thermal conductivity and unit weight, while increases the water adsorption property of the specimen. The compressive and flexural strength are decreased when the ratio of fly ash is more than 30 percentages. However, when considering the various factors it can be said that, appropriately ingredient toward produce to commercial of the good pozzolanics soil bricks is portland cement constant was 5 percentages and 30 percentages of fly ash by weight basis of soil at water per total powder, W/P 0.3525. The compositions of fly ash more than 25 percentages by weight basis of soil and since up to 14 days of curing time proved to be economical mixtures for load bearing panels or brick type structural elements according to the Thai Industrial Standard(TIS) for structural clay load-bearing tile. Therefore, commercial development is highly promising.

Abstract: Electrical resistance method was used to detect layer moisture content across the thickness of Larch (Larix gmelinii) specimen during drying, and the temperature of the same layers and the environment were also measured by remote temperature scanner. During the drying process, layer moisture content was obtained from other Larch specimens with slicing method. Layer moisture content measured with electrical method was compared with that acquired with slicing method. Results showed that the wood center temperature was more suitable than the environment temperature as compensated temperature to amend moisture content measuring with electrical resistance method; variation of layer moisture content of Larch specimen could be more or less measured with electrical resistance method, and had a relatively good agreement with that acquired with slicing method except that u₁₅ was 3% higher than U₁ and u₃ was 4% higher than U₃ in the middle stage of drying.

Abstract: This paper studies the water requirement of the two cattle manure ash in two different experiment conditions. According to the flying ash used in cement and concrete, the water requirement of the cattle manure ash is studied and the flying ash water requirement is compared when two different superplasticizers (the naphthalene-based water reducer and the polycarboxylate-based water reducer) is added into the mortar with cattle manure ash and flying ash. The result shows that the water demand ratio of the cattle manure 2 is more than that of the cattle manure 1, cement and fly ash with superplasticizer and no superplasticizer. The result provide calculation basis to the aiming mixture design of the cattle manure ash concrete.

Abstract: Recently, as the national policy of green growth is promoted, construction field also makes an effort to reduce CO₂ gas released when producing cement continuously. In other words, as the method solving environmental pollution and resources exhaustion, lots of mineral material compounds such as blast furnace slag which is industrial by-product, fly ash, red mud, etc. are examined to be used as the substitute good of cement. Therefore, this study intended to supplement the weaknesses of blast furnace slag and red mud with blast furnace slag and red mud, as the substitute good of cement, not concrete compound, manufacture inorganic composite of cement world, which can be made with only alkali accelerator at normal temperature, without high-temperature plasticity. After confirming kinds of red mud and alkali liquids and physical property by the change of addition rate with fundamental experiment, proper mix was drawn by combining blast furnace slag.

Abstract: Many concrete structures can not reach their designed service life because of their poor durability. Water and aggressive substances such as chloride ions are prerequisite to the deterioration of concrete. In aggressive environments, water repellent treatment is an effective path to delay the repair and improve the durability of concrete structures. Thousands of years ago, people used oils, animal fats or wax to treat the surface of natural stones, bricks or put some animal blood in mortar to make them water repellent. Many historical monuments were protected in these old methods. In this paper, different amounts of ox blood had been added in concrete. Compressive strength, water absorption and chloride penetration tests had been conducted. In this way, the influence of ox blood on water absorption of and chloride penetration into concrete had been investigated. The results indicated that the compressive strength of concrete with addition of ox blood decreased. And water absorption and chloride penetration into concrete were effectively reduced by adding some amounts of ox blood. The concrete with the surface abraded off 5mm, 15mm and 25mm which were mixed with ox blood had higher water absorption than concrete without abrasion.

Abstract: Two of the primary waste components of the Phosphates benefaction process, sand and clay have been used as building materials for thousands of years. A process known as rammed earth has been used extensively around the world in buildings that have lasted for centuries. Because earth is the main ingredient in rammed earth it has recently enjoyed new popularity as a so called “green” building material. In a similar process earth is compressed into blocks which are then used in the same way as conventional masonry units to build walls. In the compressed earth block [CEB] method, individual units can be manufactured and stockpiled for later use rather than being fabricated on site as in the rammed earth process. This research project will investigate the potential use of waste clay and tailing sand from the phosphate benefaction process as the primary ingredients in compressed earth blocks for commercial and residential construction projects.

Abstract: Construction industry is one of the sectors that would highly benefit from Nanomaterials with new functionalities and enhanced performances. The use of Nanomaterials in this industry should be considered not only for enhancing material properties and functions but also in the context of energy saving. This paper, aims to keep special attention on low energy buildings which utilizes the key resources of energy or construction materials in a more efficient way than the conventional buildings. Using Nanomaterials in these cases include harvest solar or other forms of renewable energy and energy conservation. The paper presents also applications of more efficient and cheaper solar energy collectors with high flexibility, heat absorbing windows, energy coatings and Nanoinsulations. The flexible insulation allowed the panels to be thin enough to fit within the existing window casements without need to modify window and roof fixtures. The NanoHouse represents a successful method of explaining what Nanomaterials are and how they work.