Self-consolidating concrete (SCC) has been used increasingly over the last two decades, especially in the pre-cast concrete industry because of its ability to consolidate without vibration even in congested areas. The development of SCC mixture design has been driven mostly by private companies who desired to utilize SCC's advantages and consequently there exists limited public information regarding the performance of SCC mixtures.The present study has attempted to present an experimental study on fresh and hardened properties of SCCs containing Volcanic Pumice (VP) as natural pozzolans which was used for both cement and filler replacements, in comparison with ordinary SCC mixture, SCCs containing Silica Fume (SF) and conventionally vibrated concrete mixture. Properties such as slump-flow, J-ring, L-box, V-funnel and sieve segregation resistance were investigated for fresh concrete and tests such as compressive strength, water and chloride-ion permeability and capillary water absorption at various days were performed for hardened concrete. The results indicate that natural pozzolanic materials such as VP can be used to produce SCCs. In addition, the results prove that natural pozzolans have enhanced the mechanical properties and durability of SCC and reduced the chloride penetration, significantly.

One of the important issues in the production of concrete is environmental variability that affects the concrete and elements constructed from this material. Due to the importance of different characteristics of concrete in short- and long-term conditions, this article aims to investigate the influence of initial temperature conditions of self-compacting concrete on its long-term characteristics and determine the initial optimal temperature of concrete. For these purposes, several experiments under three temperature conditions of 5, 20, and 40 degree-of-Celsius were conducted to evaluate the rheology and mechanical properties of fresh concrete in the range of 7 and 28 days. In these experiments, alternative mineral admixtures of cement such as micro-silica, fly ash, and zeolite were used to build the concrete specimens. Results demonstrate that the mechanical properties of the specimens increase with increasing initial temperature in the short term, while such properties significantly decrease in the long term compared to the specimens constructed under lower initial temperature. Moreover, the fluidity of self-compacting concrete increases with increasing initial temperature.

Plastic hinge properties play a crucial role in predicting the nonlinear response of structural elements. The plastic hinge region of reinforced concrete normal beams has been previously studied experimentally and analytically. The main objective of this research is to evaluate the behavior of the plastic hinge region of reinforced concrete deep beams and its comparison with normal beams through finite element simulation. To do so, ten beams contain six deep beams, and four normal beams, under concentrated and uniformly distributed loading, are investigated. Lengths in the plastic hinge region involving curvature localization, rebar yielding, and concrete crushing zones are studied. The results indicate that the curvature localization zone is not suitable for the prediction of plastic hinge length in reinforced concrete deep beams. Based on the results it can be stated that in simply supported normal beams the concrete crushing zone is focused on the middle span, but in simply supported deep beams by creating a compression strut between loading place and support, the concrete crushing zone spreads along the compression trajectory. The rebar yielding zone of simply supported beams increases as the loading type is changed from the concentrated load at the middle to the uniformly distributed load.

In this study, the concrete-steel bond strength of concrete filled cylindrical steel tubes has been experimentally investigated. 22 short, high strength and normal concrete filled circular steel tubes were tested. Push-out test was carried out as the common method to evaluate the bond carrying capacity. Four different concrete mixes were used in preparing the specimens. The steel tubes were welded type with the nominal inside diameters of 3, 4, 6 and 8 inches. According to the test results bond strength increases with reduction of the w/c ratio of concrete mixes. The high strength to normal concrete bond strength ratio increases with the diameter of steel tubes. The bond strength decreases for higher diameters in both normal and high strength concrete specimens.

The Persian Gulf is well known as one of the most aggressive environments in the world because of its high relative humidity, temperature, and concentration of chloride ions. Concrete structures are increasingly being deteriorated in this region. Therefore, improving the durability of concrete structures in this environment is an important issue. Supplementary cementitious materials (SCMs) can be useful for concrete durability enhancement in such harsh environments. In this paper, the effect of silica fume on deterioration resistance to sulfate attack in seawater within simulated splash, tidal and submerged conditions have been studied in selfconsolidating concretes and mortars containing silica fume (SF) with/without natural zeolite (NZ). To achieve this objective, self-consolidating concrete specimens and concrete equivalent mortars (CEMs) with/without 15% natural zeolite and 8% silica fume with a total binder content of 380 kg/m3 and a constant water to cement ratio of 0. 45 were fabricated. Limestone powder (LP) is also used as an inert filler in all SCC/CEMs. Additionally, both the conventional and SCC mixes were subjected to these durability tests to compare their performance. After 7 days of curing in a saturated calcium hydroxide solution, all of the specimens were subjected to three exposure conditions (tidal, splash, sub-merged) for 28, 90 and 180 days of testing ages. After taking fresh property testes of mortar/concrete samples by SP demand, slump flow, visual stability index, JRing, T50, V-funnel tests, several standard hardened property and durability tests were investigated by mortar/concrete compressive strength, chloride permeability, concrete electrical resistivity, mortar capillary water absorption and porosity tests. Moreover, the degree of sulfate attack was evaluated by measuring the expansion of mortar prisms. Traditionally, the extent of sulfate attack is quantified by the percent expansion of prismatic bars completely submerged in sulfate solution and this exposure regime used to evaluate sulfate attack is not typically representative of that encountered in the field. Wherefore, here in this investigation, prismatic bars were placed in different conditions mentioned and exposed to simulated seawater solution then expansion values evaluated. In addition, a reduction in compressive strength of all specimens was denoted by the strength differential factor (SDF). Results demonstrated that the incorporation of SF with NZ mixes in different exposure conditions led to the lowest absolute value of SDFs in all of the simulated-testing environment. Conversely, the lowest level of compressive strength at all testing ages was obtained for ternary blended cements (PC+LP+SF). Therefore, it can be concluded that SF has a negative effect on the compressive strength of SCC exposed to Persian Gulf seawater solution. This is attributed to the Mg-oriented sulfate attack which was more deleterious in SF ternary blended cements. All in all, the results were obtained from a laboratory set up and indicated that when the durability properties of the concretes in such environments were taken into account, the quarterly use of zeolite and silica fume (PC+LP+SF+NZ) provided the best performance in all exposures. Furthermore, self-consolidating concretes and mortars performed better than normal types. Besides, it is concluded that splash zones affect concrete specimens more harshly than other conditions.

Increasing impermeable levels has made water control a great challenge. On the other hand, the increase of impermeable surfaces causes the lack of heat exchange of the underground layers with the air, which will increase global warming. One solution to this challenge is to use porous pavements. Advantages of porous pavement compared to normal pavement,only on run-water control, he can easily increase the use of the road, increase the main road and increase the road, and so on. Restrictions on porous concrete include restrictions on use on high-traffic roads or heavy traffic loads,In other words, with the current knowledge about this pavement system, it can be used in less traffic routes such as local roads and streets and parking lots. The purpose of this study is to investigate aerated concrete and get acquainted with the standard related to aerated concrete. Also in this research, the advantages and disadvantages of porous concrete, construction, maintenance and common problems of this system have been required. At the end of this research, only to gain general knowledge about aerated concrete and aerated concrete pavement mix design, common maintenance methods of porous pavement and common tests in the relevant researches are introduced. In the end, it was concluded that with sufficient knowledge, porous concrete pavement can be used on roads with low traffic or light traffic load.