Abstract

Sustainable construction practice ordains the exploration of different industrial wastes as supplementary cementitious material. Nano-particles are found to enhance the properties of concrete through filler effect, better interlocking, reduction of internal cracks, reduction of interfacial transition zone, and by proving more nucleation sites for accelerated and improved hydration. In this study ground granulated blast furnace slag, a propriety ultra-microfine slag and stone dust passing through 75 μm sieve are used in different binder compositions for partial replacement of cement. It is found that such replacement enhances the properties of the concrete. The study indicates that stone dust which is an industrial waste without alternative use, has the potential to be used in concrete as a partial replacement material with cement, when used in combination with other supplementary cementitious materials.

Abstract

Transportation facilities are the mainstay for any economic progress in country's development. However, presently highways are the biggest hazard to the world as they account for a major number of road accidents. Repetitive crashes at any location on the road are known as blackspots. These can be due to numerous crash causative and geometric factors and is not an arbitrary occurrence. An effort is made to identify these blackspots on NH 44 over a 40 km stretch and audit studies were conducted at the blackspot locations. Audit study is a procedure for evaluating crash prospective, safety performance, rehabilitation of existing pavement, and maintenance of highways. The prime objective of an audit study is to identify the problems of a highway project by conducting the site inspection and collecting data from various agencies. The designer or client then studies the recommendations and a decision is made whether or not to implement the suggested safety amendments. With the aim of decreasing the escalating road accidents, the current study aids in evaluating the black-spot locations on the highway where the major road crashes occur. Accident data for the preceding five years (2011-2015) on NH 44 was collected from a secondary source in terms of time, km range, nature of accidents, road condition, and causes of crash. This data is analysed using accident severity method for identification of black-spot locations. These identified black-spot locations are ranked according to the severity of occurrence. Audit studies were conducted at black-spot locations for accomplishing advanced measures to diminish the causes of road accidents.

Abstract

Disposal of Iron ore tailings is one of the major problems in mining industry. Investigations are being done all over the world to utilize tailings for useful purposes. The scope of this work was to study the utilization of iron ore tailings in manufacture of stabilized compressed building bricks. For two types of sand like Natural sand and artificial sand, two sets of mix proportion (Mix1 and Mix2) were prepared based on the properties of iron ore tailings for the addition of various percentage of cement. Totally sixty stabilized compressed building bricks were prepared for each type of mix, all the o specimens were cured by steam using steam curing tank for 8 hours at 100 C and Laboratory tests were conducted for Density test, Dry compressive strength, Wet compressive strength, Initial rate of absorption, Water absorption, Efflorescence test, Falling test, Dimensionality test, Soundness test, and Hardness test. Finally results were tabulated for the comparison of results of each mix ratios. In all the comparisons, compressive strength of bricks made by tailing based mix was higher than the IS standard specification of conventional bricks. Similar trend was in other laboratory tests also.

Abstract

This paper aims at describing the structural behavior of shear-deficient reinforced concrete beams retrofitted with SIMCFL jackets and provides a simple analytical procedure for predicting the shear capacity of the retrofitted members. An experimental work was carried out to study the behaviour of reinforced concrete beams retrofitted with Slurry Infiltrated Mat Continuous Fibre Laminates (SIMCFL). Totally eleven Reinforced Concrete (RC) beams of size 150 x 250 x 2000 mm were casted. Out of eleven beams, two beams were considered as controlled beam for reference and the remaining nine beams were used for retrofitting purpose. A set of three laminates (SIMCFL) were casted for the combination of material like 100% Cement slurry, 50% Cement + 50% GGBFS and 50% Cement + 50% Fly ash with a w/c ratio of 0.40. The RC beams ,designed for under reinforced section were casted for M20 grade concrete with a w/c ratio of 0.45. Both, RC beam and Slurry Infiltrated Mat Continuous Fibre Laminates were retrofitted with adhesive material at the bottom of the beam, that is, after 28 days water curing. The beams were tested using loading frame of capacity 1000 kN for flexural strength. Based on the obtained enhanced results, it was concluded that the combination 50% Cement + 50% GGBFS and 50% Cement + 50% Flyash Slurry Infiltrated Mat Continuous Fibre Laminated beams can be used to strengthen the RC beams for retrofitting purpose.

Abstract

In this experimental investigation, an attempt has been made to study the suitability of fly ash and lime along with sand in the preparation of stabilized laterite-soil bricks. A required numbers of bricks were moulded with a hydraulic press paver block and brick making machine for the various percentage proportionate, such as, 75% Laterite soil + 15% sand + 5% fly ash + 5% lime, 73% Laterite soil + 15% sand + 5% fly ash + 7% lime, and 71% Laterite soil + 15% sand + 5% fly ash + 9% lime, tested as per, IS specification, and the results of dry compressive strength, wet compressive strength, and water absorption were tabulated. Based on the test results, laterite-soil bricks are more stable than the traditional burnt bricks to resist higher compressive loads. Production of laterite bricks, which do not require any special attention in the preparation decreases the threat to the environment by deforestation and Global warming.

Abstract

Research and application of hot mix is being done on a large scale across the world. In a country like India, Cold mix technology is lagging behind in both research and application fields which is quite observable. In cold mix technology, there is no heating of the aggregates and bitumen which are the prime reason for the environmental pollution as in case of the hot mix technology. Besides environmental problem, cold mix technology is economical as the heating cost of aggregates and bitumen is saved.

The cold mix can be produced using the same hot mix plant. Different agencies and researchers have developed different mix design procedures for cold mixtures with a little change in each of them. The main objective of the present work is to improve the properties of cold mix. For preparation of the mixes, aggregate gradation has been taken as per MORTH specification for BC – 2, emulsion content has been varied regularly from 7% to 10% for dense graded mixes. In the present study, a conventional cold mix Bituminous Concrete (BC) is designed as per asphalt institute manual and is compared with the cold mix bituminous concrete which is prepared with different dosages of liquid additive. The additive is varied in three dosages of 0.2%, 0.4%, and 0.6% and it is added to the bitumen emulsion prior, to mix with the aggregates and mixed with a mechanical mixer for 10 min. For each dosage, optimum residual bitumen content is found out separately by varying emulsion content. From the Optimum Residual Bitumen Content (ORAC), the specimens were made to check the indirect tensile stiffness test at three different curing conditions of, one day curing at 25 ^oC, seven days curing at 25 ^oC and 40 ^oC to check the rate of gain in strength of cold mixes. From the results obtained from the indirect tensile strength after adding the additive, there was a notable increase in one day strength.

Abstract

The objective of the present paper is to present a critical review on 3D printing types of concrete, developments in 3D printing of Concrete, legal aspects, current challenges, and future perspectives of 3D printing of concrete. Though there are many challenges, in future, Concrete printing is believed to have the capacity to change or improve the traditional construction process to some extent. Designers and architects need to understand the benefits of this technology in terms of improved design features and hence should be able to unleash their design potentiality that was previously restrained by traditional construction methods.